Hi Nix,
Tammuz is an Israeli based Surrogacy/Donor agent that work with several clinic locations abroad. I haven't heard a lot about them, but they have their own package prices and I think specialise with gay parents. Feliz mentions another agency which I know very very well and will not comment on here for fear of being sued
I have met and worked with many of the Surrogacy clinics in India, Georgia, Cyprus, Ukraine and those that I haven't worked with I generally know quite a bit about. I don't mind to answer any questions about the clinics and will be quite frank- those that have repeatedly proven themselves to be ethical, successful and operate with integrity, I'm more than happy to vouch for. Those that I think are dreadful and take advantage- I would list if I could be anonymous.
Amongst the good ones, costs vary greatly, so don't assume the most expensive are the best or the less expensive are lower quality. Number of staff, onsite or off site cycles ( their own IVF full time team or an IVF team that only performs their cycles), surrogate housing, surrogate payment, profit margin and many other factors come into costing.
Always do your homework and check message boards/Forums for feedback on your clinic- be aware that some agencies post as infertility patients to promote themselves, so use your own judgement. And always make sure there are other successful parents you can speak with- all the good clinics will have references for you.