Cash Car/ Clean Titles

I am a small business owner working in the private fleet industry. To maximize my earnings, I want to purchase below the market vehicles cash instead of financing; having to deal high interest rates and the expenses that taking away from earnings is no no in this economy LOL. The requirement is that vehicles are clean titled and no more than 13 years old

I’ve searched websites like Cars.COM and cargurus but would like to know what other reputable sources are there preferable in the Greater Houston area (worse case surrounding cities in TX).

I’m going to try Craigslist next but that feels like a dangerous game from previous experience with FB marketplace

Thank you!