YouTube can be a helpful information source. Here is a link to get you started: Pros and Cons of the four top trike brands from Laid Back Cycles. They have lots of trike reviews on their channel, as well as Utah Trikes, which has a large online business. A short list of trike brands: Terra Trike, Catrike, ICE, HP Velotechnik, Azub, Greenspeed, Spike and I'm sure I'm forgetting a big one. Most of them offer various models for various styles of riding.
Once you familiarize yourself with some of the models available, I recommend you start checking your area Craigslist for recumbent trikes. If you know what you want, you may find a bargain for roughly half of the new retail price. To figure out what would be best for your needs, though, a visit to a dealer can be helpful. Finding exactly what you want on Craigslist immediately would be an incredible stroke of luck. It's very important to test drive a few different models. Seat height varies, and with the seat height, ease of sitting down and getting back up and out of, also changes. Center of gravity around hairpin turns at speed varies with the seat height also. But if you're not going to do that, then a higher seat might be what you want. Or maybe something in between the low and the high. And decide if you need one that folds, because not all of them do. PM me if you have any other questions.
There are two other websites that specialize in online sales, Utah Trikes and the Hostel Shoppe