Magic The Gathering

There are several different formats so it depends. The format that I play most often involves large multiplayer games lasting 1-2 hours, but the most popular format is 1v1 with 30 minute rounds (best of 3 games). If you were to play Standard (the latter format), you would have to replace cards as new sets rotate out which is every 8 months. A typical TOP TIER standard deck is $200-300, but a $50-$100 deck is perfectly viable. There are non-rotating formats (namely Modern) which are inherently more costly. The investment is closer to $400-$800 (for Modern), but you'll never have to worry about rotation and you have much more time to assemble your deck. Modern is much more skill intensive than Standard and I wouldn't recommend it for beginners.

If you want to just start out, I'd recommend buying an Event Deck wherever you'd buy Magic cards. It's a pre-made deck designed to be viable in Standard and it's $15. Your store should have FNM (Friday Night Magic) where you can play against others and get help from more experienced players.

If you don't want to build a deck, you could play a format called Draft at your FNM. For that format, you take 3 booster packs and open one, choose a card, pass the pack to your left, then choose another card from the pack passed to you until you have a deck. This format is probably the best for beginners since you get to learn basic interactions and there's no high investment (it's usually ~$12 per draft). Hope I could help.

go for it

I've also fallen out of buying Magic for the time being, as I'm allocating resources elsewhere. We still play from time to time, and my decks still kick ass. Great to see this thread still going, btw! : )