Bookbub and Freebooksy seem to be the front runners but are expensive. I decided to look for cheaper alternatives and see what happens. I found loads of sites, anything over $10 I discounted as I am on a very tight budget. I found numerous sites go on US reviews not UK which I think puts UK self published authors at a disadvantage.
I advertised The Awakening on kindle countdown for £0.99/$0.99 and Origins (novella) FREE. I was hoping it might lead to purchases of The Reckoning and boost my ratings.

Here is some info on those I looked into -
Awesome gang $10
Submit to Awesome Gang
Ebooksoda $10 27th Feb
Submit to Ebooksoda
Choosy bookworm $8 26th Feb
Submit to Choosy Bookworm
Readcheaply free 26th Feb
Submit to Read Cheaply
Ereader news today - couldn't use as not enough US reviews which is a same as have a good reputation
I love vampire novels - couldn't use as not enough US reviews & too expensive as I was a on tight budget. Promos are $49 daily download, $59 free read of the day, $77 featured read.
Pixel of ink - not taking submissions at present which is a shame as have a good repuation
Daily cheap reads - need 5 US reviews & I only had 4! Boo!
Booksends (was bookblast) - not enough US reviews
Frugal Freebies - Free books - Free to submit
Submit to Frugal Freebies
Read Freely - Free books - Free to submit
Submit to Read Freely
Book loves heaven - Could not use as need 10 US reviews
Daily-Free ebooks - Free books - Free to submit
Submit to Daily-free ebooks
To be honest I was a little disappointed but glad I tried it and one positive is that I now have a US review for Origins.
I sold 13 copies of The Awakening, 28 Free Origins, 2 borrows.
Its now 23rd March and no copies of The Reckoning have been purchased.
Income $5.94 and £2.20
Spent $28
I really liked Ebooksoda, Awesome Gang and Choosy bookworms websites and their communication was good but think they are just accepting too many books so you do not stand out.
I will definitely try the free to submit sites again for a new promo very soon.
I think unfortunately it is a case of what you pay for but I just can't afford Bookbub & Freebooksy's fees and to be honest I hate the idea of paying to advertise my book for free. Its also a big gamble as it does not guarantee you will increase sales of other books in your collection.
Has anyone tried BookBub or Freebooksy?
What did you think?
Was it worth the money?
Hope this info helps some of you out there.
Thanks
Emma x