Ah, I didn't know there was a subscription (@danny!! You never said when we chatted - lol I should have guessed it wasn't free :rolleyes)).
I've used Checkatrade recently actually, and Rated People. I need some garden clearing/ maintenance work done. I liked Checkatrade's interface better. You can choose up to 4 companies to call you back. Describe the job to them and they call you. Testimonials/ reviews are really easy for future customers to have a read through when choosing.
Having said that, a man came to quote, great price but when I tried to contact him to go ahead - nada! It would be mean of me to write anything on his profile but this is an important factor because now I am having to go through the whole process again to find someone else. (And I have and it's booked - so let's hope he turns up!).
Rated People - the professional has to pay each time to get full details of a prospective job. I think up to 3 can show interest - lol I got none! So then I started getting emails from Rated People, telling me what a sh!t job it obviously was as no one had paid to find out more. (Well they didn't exactly say that - but that's how it makes you feel as a customer).
Anyway, if you're just starting out then look at cheaper options although really any form of advertising is not cheap - I know! Look at it as an investment. If you only got 2 jobs from it, it would almost pay for itself... And if you do invest in it, make sure you check it regularly, be quick on the follow ups and that in itself can then lead to word of mouth referrals - not everyone knows someone who knows someone in a trade that they are looking for.