for what it would cost to have a gunsmith install sights, you could buy another .22 LR at Walmart and have two guns then.
The Mossberg "Plinkster" is a decent little rifle for not much more than 100 bucks... we've got about 4 of them in our immediate family, and everyone likes them.
As for learning to use your scope... the first thing to learn is that you need a "full moon" view. If you see a crescent shadow at top or bottom, or on either side, you're gonna miss... the shot will strike away from the crosshairs.
So practice with your "eye relief" until you get the full sight picture (no shadows)... and just practice at 25 yards on a paper target until you can shoot the smallest groups you're able to (they should be 1/2" to 3/4" max at 25 yards).