Thats because Authorize.NET is sold through a network of resellers who pretty much dictate the rates. If you contact Authorize.NET directly though you will be directed to a sales rep who can disclose rates.

Heres a ballpark of what you can expect with them:

Merchant Account ~ 2.4% per transaction + $.25 per transaction + $10/month

Payment Gateway $100 setup + ~$20 a month and.10 per transaction

You will need them for a Payment Gateway, but you may have a merchant account with someone else (for instance Paymentech)

I have had good experience with Auth.NET in the past and they seem to be a good value for medium transaction volume ecommerce sites.

Yes, we went with Wells Fargo and they gave us an excellent custom quote (much cheaper than web site suggests). No setup fees, fixed $31/mo and $0.20 per transaction. We have our limit though, and once we exceed it the price will go up.

What do you mean with 'limit', exactly?

To enjoy those lower fees we must stay under a certain number of transactions a month and (I believe) we have a max. limit on a transaction amount. I apologize for being unable to give you full details, since my partner is finalizing cost issues with them as I'm typing this.