Budgies/parakeets and cockatiels are great little birds. They can be extremely affectionate and some are very talkative. They’re not nearly as scary as some of the larger birds can be - have you ever looked at the beak on a parrot? Think about that nuzzling next to your eye, because they’re going to.
They don’t need nearly as much time and attention as the large parrots, either. You still need to play with them every day, but not all day.
They’re also not nearly as destructive as the larger birds, who usually require things to tear up if you want to keep them from starting on your house.
In general, you only want one bird at a time, if you want them to interact with you. If you get more than one, they’ll tend to socialize with each other rather than you. But if you can’t give them the attention they need, get a pair. Just don’t expect them to be all lovey-dovey with you when they’ve got a bird pal.
And training birds can be an exercise in frustration. Very good for the development of patience, though. There really isn’t any way to effectively discipline a bird, other than to ignore the bad behavior (at most, separating the bird from yourself) and reward the good, and wait for them to decide to be good. They’ll talk if they want to, do tricks if they want to, etc. Fortunately, since they are social, if the bird wants your attention (and it does!) it will cooperate. Usually.
For instance, to potty-train a bird, you watch it carefully whenever it’s out. When it poops, immediately return it to its perch or cage and ignore it for a bit. Don’t yell, don’t scold, don’t do anything else.
You’ll soon learn the warning behaviours that the bird is about to poop. When you see the warning, get the bird to its spot before it poops, and then praise it for going in the right spot and bring it back out to hang with you. Eventually, it will either take itself to the right place, or be sure to warn you so that you can get it there. Unless it doesn’t feel like it.
After your initial investment for bird, cage, bowls, etc., they’re not terribly expensive to keep. But that initial investment can be fairly high - I doubt you’ll be able to do it for $50.
Before you get a bird, find a good local vet who sees birds. Finding a vet for exotics can be very difficult - you don’t want to wait until you have a problem.
Do some research on your options for obtaining the bird, also. Don’t buy one from Walmart or Petsmart or one of those places. In the first place, it will probably die shortly as they’re notorious for not taking care of birds. In the second place, you don’t want to encourage them to sell animals they won’t take care of.
Find a good local breeder or pet shop, or one of the rescue groups. Any of those should be more than willing to help you pick out the right bird for you, based on what you want and your lifestyle, and get the proper supplies. Most of them will have a some sort of return policy, if you find out in the first few weeks that a bird is not for you. They’ll be very interested in making sure you’re happy with your bird, because another bird-lover is a customer for years!