We used Darren Carr @ Amistad expeditions and it was $480 for six of us and I was happy with their service.
http://www.amistadexpeditions.com/#!shuttle/cfvg The rentals were $65 a day and they were nice kayaks. I used a cuda 12 because I already had one but 3 people I went with rented these Coosa's and they are perfect for the river. I have since then acquired a coosa for small waters. You can never have to many kayaks
http://www.amistadexpeditions.com/#!kayaks/cpf5 This was 100% my fault for not understanding the process but the biggest headache was coordinating the permits with the State of Texas and the outfitter. Bottom line is the the state will not take your reservations until you confirm you have an outfitter booked but the outfitter doesn't know how many permits have been issued so they could accept your deposit for a specific day and the permits have already been issued. The state only allows 12 people (I think that is the correct number) to be dropped off in the river per day.
My suggestion would be to get Plan A dates and Plan B dates nailed down that your group can go. Then call the state (be prepared to be on hold. I called 3 times and was on hold over 45 min each call before talking to somebody) to verify that the permits are available for both Plan A and B days. Then call the outfitter to see if they can take you that day and pay your deposit to the outfitter. Then call the State back
IMMEDIATELY and buy your permits and hope somebody didn't call in between those two times our your up a creek and you will have to reschedule with the outfitter.
I tried calling the State right after I paid the Outfitter but was on hold for more than an hour and didnt get to try again until the next day. Turns out the permits were already issued and so I had to call the outfitter back and reschedule and then call the State back and pay them.
Hope that all made sense. Overall it was well worth the headache. Absolutely beautiful river.