I have received a lot of questions about online auction platforms for small nonprofits. If you do not have donor management software, need something easy and fast for your auction, I found these sites to have good options. I like different ones depending on what the nonprofit needs.

Auctria.com
It as a very nice look and feel for basic auction site. It is nice to have event night phone support, they design the site.
Free version has 3 users and 1% credit card fee, no texting capabilities, up to 250 bidders, silent and live auctions, it does not do raffles on any level
$300 /year – has texting, custom emails, 10 users, up to 750 bidders, can track sales tax and consignment, .5% fee on credit cards. Smart choice for you if you don’t have a large audience, want minimum cost and a good look.

Silent Auction Pro
Provides services for online donations, online auctions and some donor management.
$647 annual fee covers an online auction fee that is a pretty robust tool. They charge 2% for each transaction. It includes unlimited number of users. Online site, online photos. It allows for ticket sales as well. For an upgrade to $796 it posts banners and sponsor logos. Smart choice if you need it for a large group of donors (over 400) and expect to have reach around 1,000 at the event.

Better Unite
A donor management system with an auction module. The tool works for in person and virtual auctions, so if you need it for next year too, you don’t have to change where the data is located. The virtual event tool is better than most, if you want to have the complete hosted feel. Cost for the plaltform is free. But they charge 5% for a transaction and it is capped at $20 on a transaction. The system asks bidders to support the tool in addition to supporting your event in a ‘tip.’ The 3rd party merchant services provider tags on an additional 2.9% fee. Good for you if you don’t have donor management and you do a lot of events. The additional cost helps you year round.

Bidding Owl
Used by a lot of schools and others that want something easy and inexpensive. The look and feel is a little rough, but the cost is very good. Base cost for the auction only one time use for $10K in donations is $500, then 5% of the auction price. Everything else is at no cost. Good for all volunteer type of programs where you don’t have strong technology skills and not much time.