The Big Ones
Flippa - This is flea market #1. Largest amount of listings but absolutely no curation or due diligence done on any of the listings. Some sellers do connect their GA and Stripe accounts but not all. You really have to be careful here. Like in any flea market, you can find some great deals here but you'll have to spend a lot of time filtering. Listings include domain, content, SaaS, apps, ecommerce, and affiliate properties. Typical asking price is $1k - $1M. Today, this is the most popular platform to acquire a website.
SideProjectors - Flea market on the other side of town - #2. This is a marketplace where people sell their side-projects. It has a lot of listings and no vetting. You can find websites, blogs, ecommerce, SaaS, themes, plugins, and other types of projects. Some listings are looking for a co-founder. Typical pricing is < $10k.
IndieMaker - Flea market #3. Similar to SideProjectors but a bit higher quality of listings. You can buy any type of project here including websites, apps, code, domains, SaaS. Large selection but everything is DIY like the other two flea markets. Easy to browse, view listings, contact seller. Typical pricing is <$50k
BusinessesForSale - Founded in 1996. Claim to be the largest marketplace with ~57k listings. Listings includes online, brick & mortar, service, and franchise. They list businesses from many local and smaller brokers in addition to their own. Listing detail really depends on the broker. A lot of listings but they have features to help you sort through them. There is some vetting of the listings but not always reliable.
WebsiteClosers - Founded in 1998. Focus on website properties including ecommerce, affiliate/content. Most listings have a detailed qualitative writeup which is a nice feature. They'll help you with DD. Good case studies and resources. Typical asking price is $50k - $3M.
The Blue Chips
FE International - Founded in 2010, they provide broker and M&A advisory in US and UK. They do curate their listings and you'll see higher quality and higher valuations. Not a large marketplace but includes content, ecommerce, SaaS, and affiliate properties. Typical asking price is $10k - $5M. Not many DIY features but they'll help you with any questions and acquisition. Excellent blog and other resources. Full service brokerage.
Empire Flippers - Curated collection of listings including ecommerce, content, and affiliate properties. Not a large marketplace (~80 listings) but easy to use with clear listings and data. You won't find starter websites here. Feels like they price their listings higher than other brokers but they do offer higher quality listings. Full-service brokerage. Typical listing is $50k - $2M.
Quiet Light Brokerage - Highly curated collection of listings. Typically has 3 - 8 listings at any given time. Can find ecommerce, affiliate, and SaaS properties. Typical listing price is > $1M. White glove service as they'll help you source, negotiate, and acquire a listing. Excellent podcast.
Motion Invest - Vetted marketplace of content/affiliate websites. Spencer Haws of Niche Pursuits is a co-founder. Easy to use with a lot of detail in the listings. Typically has 3 - 10 listings priced anywhere from $5k - $200k.
Investors Club - Vetted listings with good detail. You have to become verified to view full listing details. Focus is on content/affiliate websites.
Latona's - Vetted cash-flow positive online businesses. Wide variety of listings including content/affiliate, ecommerce, domain, lead gen, membership, SaaS. Does have overlap with some other marketplaces. Typical listing is $300k+. Good blog and podcast.
SMERGERS - Vetted marketplace of middle market businesses. Over 6,000 listings including online and offline businesses globally. Some listings are looking for investment or debt. Full service brokerage. Great resources and blog.
Niche
Fameswap - Instagram accounts & YouTube channels.
Shopify Exchange - Shopify. As the name implies, this is a Shopify owned marketplace. All data is verified directly from Shopify.
SwiftExits - Shopify. Pre-launch currently.
Blogs for Sale - Blogs.
Letterxchange - Newsletters. Not sure how this marketplace is doing as I've only seen one listing here.
Duuce - Newsletters. Unless I'm missing something, this is the largest newsletter marketplace right now.
MicroAcquire - SaaS. They started with a focus on SaaS but I do think they've expanded their listings in the last few months. Costs $250/year to subscribe but worth it if you're really in the market for a business. I've purchased a business here and it was a smooth transaction.
bizdaq - UK. Includes online and offline.
DotMarket - France. Mainly websites.
AIM Digital Group - UK. Not a lot of listings but they'll help you source a deal.
AppBusinessBrokers- Apps.
Fliptopia - Apps. Owned by Apptopia.
SellMyApp - Apps.
Afternic / DomainMarket / Sedo /
Odys - Domains
Expired Domains - Domains. Search engine for expired domains.
Others
Facebook Groups & Communities
The best deals can be sourced by directly contacting the potential seller without using a brokerage/marketplace. This isn't something you'll read in any of the blog posts on brokerage websites.
Source: Reddit