As a keyboard player I would encourage you to get a used keyboard that has internal sounds and midi out so it can be used as a controller for VST's.
If you are thinking Keyboard vs Piano ( in other words you really just want to use it for the many different sounds it makes including piano but aren't really interested in the nuances of playing a real piano and the velocity / weighted keys things) Then you don't need to look for one with weighted keys.
Brands that won't disappoint and should give you decent use for a while are Yamaha ( my favorite) Roland, Korg, Alesis and Casio ( yes casio they make some great keys with some great sound banks) If you get a controller with no internal sounds you are forced to connect to a computer of some sort and that is an added layer of learning curve....keep it simple and just be sure the keyboard has midi out IF you want to connect to a computer. Offerup and FB Marketplace are the go to's these days for used gear...Craigslist is getting pretty bad but always worth a daily peek till you find what you are looking for. Try to get something that is less than 5 years old just because the keys on all of them at some point start failing..Once you've found one that seems right do a quick google and check out reviews and opinions on that particular model.
Regular sized Keys
at minimum 61 keys going all the way up to 88
If you're just starting out and just testing the waters do not spend more than $200 and a good starter can be had anywhere from as low as $50 to $200
Good luck!
BTW I've been buying and selling keyboards for the last 45 years. I rarely ever buy a keyboard new.. always can find a slightly used killer board for at least 30% less than retail...I'm cheap
