So, here's the current players in the space:
FB Marketplace is becoming extremely active. Free, but most leads are delivered via Messenger and if you don't have someone dedicated to answering them you'll miss out. They also generate a lot of single response leads that go nowhere. We are approved inventory partners and include it in our used vehicle marketing platform.
letgo PRO: Currently free. We are Premier Partners and include it in our used vehicle marketing platform. They are likely adding a pay to play pricing model in the very near future, but likely with an entry point of 99.00 per month. They deliver a lot more phone leads, with a click to call number. This is the 2nd most downloaded app in the US and the lead counts are really high. Same issue with a lot of the chat leads, but the SMS and phone leads are strong.
Craigslist: 5.00 a post...and thank goodness it is. When it was free it was the wild west, now its a legit marketplace that franchise and independents alike have a ton of success on. I've got Top 5 Dealer Groups using it...and small lots with a dozen cars using it. You can drive measurable website traffic, brand, phone and SMS leads, and more. The key to finding a vendor here is that a 5.00 post costs 5.00. We include this in our used vehicle marketing platform (and don't mark up your ad budget).
OfferUp: We are working with them now, hoping to finalize a partnership so we can include this in our platform. They have a cool site/app and have some nice automotive features built in. They claim they are responsible for 10% of the car sales in the US...a number I'm extremely skeptical of, but the platform is still pretty sharp.
One thing that we do that makes a big difference, we have a unified messaging platform. That way, your Craigslist text leads, letgo chat leads, FB Marketplace Messenger leads, etc. all go into one app...you don't have to keep 3 or 4 different chat apps open all the time.