Do you think I should invest in my own drill?
Well I guess that depends on whether or not you intend to continue drilling holes in things
But if your neighbor doesn't mind doing lil' things like this for you, then I'd say no, don't buy your own (Unless your asking him/her every other week)
Drills (cordless or corded) have come down in price and now start around $25, with a cheap cordless drill starting around $40. If you choose to buy one, select a brand you've heard of (Black & Decker, Ryobi, Makita, Dewalt etc.) Stay clear of the cheap "no name" drills, they don't last and are impossible to finds replacement parts for.
Keep in mind most drills do NOT generally come with drill bits, so you'll need to purchase a small set of those too. (I recall seeing some companies selling "packages" with drill, charger, 2 batteries & a basic bit set).