Portability is a big one if you plan to move things around. Look for something that's versatile and that has decent reviews. Unfortunately, there's been an influx of fake reviews on Amazon and elsewhere, so you actually need to read a few of them instead of just going by the rating.
Lighting kits are great! They've gotten so affordable that I actually recommend them for amateurs too as a key ingredient to taking beautiful images. If you're simply looking to enhance your photos, then consider trying the Bolt VD-410 Manual Flash. You can do a lot with it and it won't break the bank.