My friend, the whole purpose of your first gun(s) will be to learn,,,
Buy any centerfire gun and you limit your learning by the cost of ammunition.
My suggestion is a .22 semi-auto rifle,,,
a .22 handgun be it a revolver or semi-auto,,,
This will not cost you too much money and the ammo is cheap.
I recommend a Ruger 10/22 rifle ($200.00 bucks),,,
Or a Mossberg 702 Plinkster ($129.00),,,
Or a Marlin Model 60 ($145.00)
Then consider a Ruger 22/45 for a handgun ($239.00),,,
Or a Ruger Mk III ($329.00) in one of the many configurations,,,
And you don't have to go the ultra-tricked out versions of them either.
I own some seriously fine handguns in my cabinet,,,
But the pistol I have the most fun
with is the basic 22/45,,,
And it's a wonderful trainer for serious practice with seriously cheap ammo.
Get the basic versions that won't break your bank,,,
Later there will be plenty of time for the super-spiffy wonder guns
Your goal should be to shoot a lot of bullets,,,
Learn the basics of good technique,,,
And have tons of fun!
You can do a whole lot more of those shooting actions,,,
At 3-4 cents a round than at 20-30 cents a round.
I guarantee if you walk out to your shooting spot,,,
Sporting a 10-22 rifle and a 22/45 pistol,,,
You will walk tall and have tons of fun.