First of all, welcome to the forums. Please note that the forums are completely independent of Enuuk itself.
As for hosting providers - I would recommend that you look at either a dedicated server or a VPS (Virtual Private Server) - as a shared hosting provider is unlikely to be able to cope with the memory, CPU and traffic requirements of a successful auction site.
Personally, the best value hosting provider which allows you to get exactly what you need is UK2.net
- particularly if you are based in Europe. I have set up 4 servers with them to date, and have found them extremely helpful, quick to respond to support requests and good value.
Realistically, you need to be looking at 4GB RAM and 2GHZ CPU as a minimum for development purposes, and then upgrade to 8GB RAM and 8GHZ CPU for a live auction site. Their dedicated servers also offer good value for money at the moment, and may suffice if you ensure that they do regular backups for you.
As for costs of the RWAP Services Modules - there are some free modules detailed on these forums -
The chargeable modules I offer are detailed at the link at the top of the forums - RWAP Services Enuuk Modules
- this provides details of each module plus charges (excluding installation).
As for developers - well there are several people on the forums who will be able to help (including me) - I have now developed 5 different Enuuk platforms, and contributed to at least 3 more... Other developers are detailed on the Enuuk website