Tom,
Would be nice to have the option to purchase phones through Swappa. Prices are much better.
Swappa prices are better than whom? eBay?
eBay will be great!
Imo Amazon is the best (provided that you actually get your money 
). Their prices are usually pretty competitive, but what really hits home is the ease of buying. No other company accommodates like them. 2 day shipping, easy returns, confident buying. Unlike eBay, swappa..., You know what you're getting, no questions asked.
I think Amazon, or something similar, is almost a necessity for phone purchases within the current multiple-deposit method-- one can't count on an Ebay listing remaining available for that long.
Even for smaller amounts that could be done in one transaction, even a day or 2 could miss out on a really good deal on an Ebay listing. It would be nice for things like Red Pocket/SpeedTalk/Tracfone, where the seller is frequently a company store.
Similar issue for Swappa, where a listing is typically one-of-a-kind.