Model 4 without Floppy Drives

I'm pretty new to the world of TRS-80. A while back I purchased a Model 4 in near mint condition. It turned out to be the base model, which did not include disk drives. I'm now looking for options on how to make the system usable beyond the built in BASIC ROM. I keep an eye out on auction sites for pulled floppy drives. I'd like to have a way to just load programs via the cassette port like I do my Apple II, but I haven't been successful with that yet.

Any advice recommendations?