>>1753320If you want to keep them close to you (like in your house) you can buy them from places like this:
https://www.exoticanimalsforsale.net/opossum-for-sale.aspBUT it isn't hard to live trap a bunch of them in the wild and transport them to your property. You just need a good area and a bunch of traps.
https://www.havahart.com/how-to-trap-opossums#selectObviously when you get them you want to make sure they stick around but not vandalize your trash, so you should leave some food for them in various areas while securing your trash someplace out of reach. Get them used to a feeding time and maybe associate it with a sound like ringing a bell or a triangle as you dump out their food.
Baby opossums are the easiest to tame, it isn't hard to raise them to trust you. (IIRC DinoTendies was lucky and rescued a bunch of babys who's mother died)