IS there a reasonably priced service that allows selling on eBay (US), Amazon and my own zen-cart store? I'm not a power seller by any means, and we are liquidating our stock to pay bills, but being able to sell on these venues from ONE place could help us a lot. We have 10s of thousands of items to sell. I currently love using Selling Manager Pro for eBay, but I can't schedule auctions in advance unless I pay the additional .10 a listing.... come on eBay, aren't ya getting enough of our money to begin with ! If I'm going to have to start paying more in fees, I want more in productivity.
ChannelMAX is almost completely free but has lots of features. You shouldn't expect the support of the high end services you mentioned but it might work for you. The downside is that ChannelMAX doesn't claim Zen Cart support.
Auction Lister Pro specializes in integrating eBay selling with sCommerce, CRE Loaded and Zen Cart so fits the bill apart from the Amazon support. It's a free and open source package.
BTW, sorry to hear you are liquidating your stock.