An incredibly common question, and one we tend to discuss with every client at the start of a project. Managing expectations (including your own), is a really important part of engaging in a PPC campaign.
The first thing to appreciate, is that every single industry will have a different average cost per click, and a different average cost per conversion. Before you spend a single penny on PPC, you need to answer one question.... and you need to be sensible about how you answer it....
Q: What is an acceptable cost-per-conversion to you?
As you are an accountant, a conversion would most likely have to be considered as a 'firm lead'. i.e a genuine inquiry for a potential (new) client.
Now...the answer to that question, very much depends on your average client's worth.for example;
How long does a client generally stay with you?
In their lifetime, how much money do they spend with you?
From that spend, what is your mark-up /profit? (i.e after employee costs etc)
Answering questions like the above should allow you to come to a reasonable assumption about an acceptable cost per conversion. It is crucial you are realistic....i.e don't expect to gain conversion for £5.
Once you have an acceptable cost per conversion, you need to know (or assume) your website's conversion rate. This is critical. i.e
Q:How many visitors (on average) does it take to your website before you gain a conversion.
For example, if you get an average of 2 enquirers for every 100 visits to your site, your average conversion rate is 2%.
If you dont know the answer to the above question....your initial spend on Adwords is going to be a market research exercise until you CAN answer the question. So..make sure you have analytics setup correctly, and conversion tracking configured.
Finally, you need to know the answer to one more question;
Q:What is the average cost per click for your target keywords.
i.e how much are you going to have to pay for a click on one of your Ads. This can very from pence, to £10s. If you are selling pencils expect to pay pence, if you are selling mortgages expect to pay £10s. Expect your cost per click to be higher at the start, and lower as your campaigns are optimised.
So...if you can answer the above, you will have some decent targets for an Adwords campaign. Let's assume for example...
Your site converts at 2%
Your acceptable cost per conversion is £200
The average cost per click for your target keywords is £3
This would allow you to estimate that for your £500 spend, you should look to gain around 3 general enquiries....obviously converting them into an actual customer will depend on factors like your sales technique...if you answer the phone....your prices etc etc.
Now the trick with Adwords is optimisation...... not all of which can be done from day one..... but some techniques which will get the cost per click down include;
Finding cheaper yet relevant keywords
Using the display network
Remarketing (which is a no brainer by the way)
Improving your quality score
Testing multiple Ads
Properly segmenting your campaigns and ad groups.
Dont be tempted to start spending money before you have done some research as above, and make sure your are realistic about your goals. If your acceptable cost per conversion is unrealistic, and your are competing against people who have a more realistic cost per conversion, it is likely that Adwords wont work for you.
Hope the above helps.