Hello and welcome to the forum -
Obviously, the printer must be 'air print' compatible, so check this
Apple Support Article for the brands and models that have this printing feature - there are numerous choices, so you'll have to decide on the brand(s) you like, the features needed (e.g. do you want just printing or a multi-function machine), and your price range. Then pick a handful that meet your criteria and do some web-searching for reviews (
Amazon, PC World, PC Mag, etc. are some obvious choices).
I have a Canon Pixma inkjet & a Brother laser printers attached to our desktop computer (via USB) - neither are 'air print' compatible, but I can easily print from the iPad using a program called
FingerPrint; the older version was $10 (the one that I'm using) and resides on your computer (nothing needed on the iPad); so, if you own a non-air print machine(s), then printing from the iPad is still possible.