FB ads can be started quite cheapily - Around $3 (or £5) per day. And should bring you a return on that investment.
Always start with social proof and run an ad for a few days garnering likes and comments. Then once your pixel has been improved start to target conversions again with the same amount o budget.
Total should run you to around £50 - £200 and can be done for much less (if they don't convert scrap it and start again)