First question is do you already have an AR-15 in 223?
If so, then it can be as simple as buying a conversion kit (I've been happy with my CMMG stainless kit) and dropping it in your upper. There are a few things you can do in terms of polishing the rails of the kit to make them pretty reliable. Negatives to that are a twist rate not ideal for 22lr, and the amount of junk deposits that end up in your gas tube and receiver. That said, when you are done shooting 22lr, you can drop your normal bolt back in and fire a few rounds of 223 to clean out the system... mostly. If you have a super safety in your AR, they can be made to work with these kits (but I'd recommend the next option if that is desired).
One step up from that is to build a dedicated upper in 22lr (again if you already have an AR lower). You'll still need a conversion kit, but also a dedicated barrel adapter/collar, as well as a barrel. This doesn't have to significantly increase the cost, upper receivers are pretty cheap, barrels can be found for under $100, then you'll just need a forearm. Set up a budget, build within it. With this route you'll get better accuracy, and I've found slightly better reliability than the fake bullet chamber set-up above. Building an AR upper in 22lr is extremely simple, there are no gas blocks to align or tubes to install.
Next and easiest option is to just buy the Tippman you mentioned (sorry I don't know anything about them) or a S&W M&P 15-22 which seem to be liked by the people that own them.
I started my AR-22 journey with a conversion kit in an existing 223 upper. Within a year I built a dedicated upper with a 16" M4 style barrel. I just recently rebuilt it with a pistol length barrel for my SBR since I just got a 22lr suppressor. I'm probably going to change to a quiet collar from BoreBuddy soon.