Great Question - and also difficult to answer.

I mean - how long is a piece of string, right. It is a bit like asking 'how much does it cost to build a house'? Obviously, there are many different styles, sizes and finishes of houses, so...  how can one put a price tag.

What is the aim of the social media campaign, who is the target audience/avatar and the CTA...  desired outcomes?

All this determins what, where, for how long...  and whether one can implement a mixed organic and paid campaign to achieve the desired outcomes, how many platforms and whether we can borrow audiences or create suitable partnerships too.

Essentially, the old saying of 'when you pay peanuts, you get monkeys' rings true. So, while there are different costs of developing and implementing a campaign depending on the level of experience, size of agency and the like, it also depends greatly on the content, advertising budget and strategy as to how much money you will have to invest in rolling the camapign out and to achieving its aim.

While it is a great question, one that gets asked a lot, I am not able to give an answer per say...

However, we recently ran a campaign for an event held on the Sunshine Coast, which wanted to do two things, drive traffice to the ticketing site and introduce its new brand. And, we did this across Facebook and Instagram, plus Meetup and using both organic content and paid ads aimed at different target audiences.

The result was a diversified camapaign that cost around $450 in ad spend plus organic outreach and a management fee of $1450. It gained reach across thousands of target audience members right across their target area, got over 6500 hits on the ticketing page, was a sell-out event which also created over 450 followers and was merried up with an extensive PR campaign (around $2250) that earned them extensive exposure from Brisbane to past Gympie, incl. 4 radio interviews, a TV interview, and coverage across 6 newspapers and publications.

Brand awareness grew massively and if the event had capacity to host more attendees, it could have been sold out twice or trice over - but didn't thanks to Covid-19. But the overall campaign did get the results they were looking for and it was definitily done on the cheaper end of the scale.

Best to talk about your campaign to get a more relevant idea on strategy and hence cost.

Over to you!
 

That is a decision you will have to make, you can do it yourself but just because you have a personal Instagram account doesn't mean you know how to run a business on Instagram. You'll need someone to maintain all of your social media platforms, create content, monitor reviews and comments, and make sure everything is running smoothly. Chances are, you don't have the time or bandwidth to do all of that and run your business so you can hire a freelancer or agency to help since they know how the world of social media works, and then sit back, relax and watch your follower count grow.  It comes down to priorities and budget, good luck.
 

The best way to forecast anything is to follow this path (1)Reach cost > (2)Engagement > (3)Sales 
(1) Cost of reach. Listen to the metrics, when you begin a campaign in any social media platform you can forecast the reach and cost (close enough). 
Let's say you need to drive traffic and you are going for Clicks and the CPC is $7 on FB/Insta. If you have $7000 to spend in media, that would deliver 1000 hits to your website.

You can obviously do the same for CPM(cost per mille aka thousand). So a $7 CPM would mean the same $7000 would deliver 1 million views ($7k / $7) x 1000. But no guaranteed clicks.

(2) Engagement. This 2 fold. At the platform level (Facebook might be 1% when considering CPM) followed by the website conversion level, which on average is 0.5% in Australia.

In the first example you can assume the platform will deliver 1000 hits, because Facebook never fails in spending a budget. Once those 1000 browsers come to your site, you can expect an average site to convert 0.5% or 50 of those 1000 hits to clients.

(3) Sales. If your site converts at 0.5% (which you can tell from setting up goals in Analytics) you then multiple sales by RRP. So if you selling a $50 items 50 x $50 is $2500 turnover from a $7000 campaign (not good). If you are a service and your service costs $1000 that would be 50 x $1000 or $50,000 turnover from a $7500 campaign (much better)


Then there is LTV (Life Time Value). How often do customers re-buy or stay loyal? They may only spend $50 on the first sale, but if they come back on average 3 times in 3 years, that same $50 customer is now worth $200 in the customers life time ($50 spent once, then returning 3 times)

Once you forecast, or run a trial campaign and have results you can then apply a CPA (cost per acquisition). In the above example we spent $7000 to secure 50 clients. To calculate it is $7000/50 = $140. This now means you are spending $140 to secure 1 client who will spend $50 - THATS A LOSING PROPOSITION. Unless they come back 3 times and spend a total of $200 in 3 years, which means you spent $140 upfront to return $200 in 3 years.

But there are other values and considerations such as; 
- Obtaining client data to launch a re-marketing campaign
- Client data to add to email/phone and follow up lists
- Awareness
- Brand uplift
-Virality, forwards, shares etc

Once you determine a fair value on the cost to acquire 1 client which is done by calculating the profit margins on products/services and how much of that sale should be dedicated to securing a client, you can build a marketing budget. This then allows you to know how much you should allocate to Facebook, or perhaps selecting another channel.

This is 1% of what we go into when building a campaign and suggesting client budgets. It may not even be paid social, it may be organic posts and paying for boosts etc
You also need to consider saturation.

Assume you are in hospitality, who on average spend at least $5k on social media a month. Deciding to run with $1000 a month will mean you have limit exposure, although if your product (or offer) is compelling enough you may generate enough product to increase your spend.

I hope this is a good starting point and shows a marketers mindset and how we start mapping it out for clients.

 
 

I am actually in the process of building a calculator for clients so they can compare apples with apples when comparing marketing strategies. I shall link once it is completed :)

Thought you might be interested in this question @Darnelle O'Brien @Erik Bigalk @Megan Edwards @Paige Arnof-Fenn @Cate Scolnik @James Norquay