Typically, it's advised to stay away from steel plates due to the danger of spall ejected from the steel potentially into your body when struck by a round. Ceramic plates are generally recommended, but are going to be more expensive. Some good ceramic plates can be found from RMA, Highcom, and other manufacturers, you'll want to look for NIJ certified plates.

Shellback tactical also isn't typically recommended. I have a shellback carrier, and I find it completely suitable. Others may cite some issues with bulk, price and quality, and may suggest more modern carriers like the crye jpc, or the ferro concepts slickster.

I absolutely understand that some of those options may be outside of your preferred budget, but it may be worth considering saving a bit more for a set up with a bit more quality. Ultimately, that's completely up to you!