Selling your used car privately can be more lucrative than trading it in at a dealership. , and there’s nothing worse than who want to offer you a case of beer and several grand less than your asking price. I think I’ve come up with a method to weed out these tire-kickers so you can focus on more serious buyers.

I work with a lot of customers who, due to a variety of reasons, would prefer to sell their car privately rather than trade it in at a dealership. The tip that I give the most often is very similar to one I use for maximizing trade-in value. The key is to get some bids ahead of time, so you have actual offers to compare. When evaluating what your car is worth, there are resources like Kelly Blue Book and Edmunds to give you a range of values based on your vehicle’s age, miles, and equipment. However, these “book values” are a bit theoretical because they aren’t actual offers. The old saying is true: Your car is only worth what someone is willing to pay for it.

This is where online retailers like , and come in. In many cases, these retailers will give you an actual offer on your car without having to leave your house — all you have to do is go to those respective websites and plug in the relevant information. Those online offers can give you a sense of what your asking price should be when you list your car privately, and you can even use the top offer to set a floor for what you’re willing to accept from a private buyer.

Last year, my wife and I inherited my late-father-in-law’s 2011 Buick Lacrosse with about 75,000 miles. We had a lot of things to manage with the estate, and selling the car on top of all that was not something I was looking forward to. I didn’t want to just sell it to a dealer, knowing that I would be leaving money on the table. Luckily, one of my father-in-law’s neighbors had a family member who needed a car, and he reached out to me.

Of course, the first question was “What do you want for it?” I had the offers from Carvana, Vroom, and Carmax ready at hand, which made the price negotiation so much easier. I sent him a text with a screenshot of the highest bid, which was about $6,800, and told him I would like to get $7,500. He countered with $7,000; we had a deal, and I was happy to see a good car go to a local family.

I was fortunate that I didn’t have to deal with calling and texting with low offers, just to see if they could pick up a bargain. Even if you do decide to advertise your used car on one of these community sites, having firm offers on hand from an online car retailer will allow you to filter out conversations with buyers who aren’t serious. Keep in mind, these online offers are typically only valid for about a week, and while your car’s value isn’t likely to dramatically change within a handful of days, an outdated Carvana, Vroom or Carmax offer may no longer be a valid benchmark for a car that has been listed for sale for several months.

A methodology that I haven’t tested, but that might work for you, would be to post the highest e-retailer bid as a photo on your ad with an upfront disclaimer like, “The highest bid I’ve been offered on this car is X. Only contact me if you have a more competitive offer.”

Of course, if you’re selling something that is really old, or a specialty car where finding comparable prices is difficult, honing in on the right price will be more challenging. But if you are selling something relatively new, in the $10,000-and-up range, having these offers on hand before you advertise is a good place to start.

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Tom McParland is a contributing writer for Jalopnik and runs . He takes the hassle out of buying or leasing a car. Got a car buying question? Send it to [email protected]