Don't start off even buying little trees at big stores without some knowledge. It's important to understand why trees are grown in special mixes (not 'potting soil'), why watering can be a major learning curve - no one a week juice glasses and forget it til next time - and why you need to understand about climates, seasons, many many different species, etc. etc. You'll be going in the right direction when you know what to look for in a tree (that you want to train for it's future as a bonsai, rather than a ready-made one with no personal satisfaction involved) when you realize the best place to shop will be a local nursery, not for "bonsai" but for young trees to grow either in the ground for a while to fatten up their trunks, or to grow in 'training boxes' (more portable, but still better than any little pot - bonsai pots are meant only for established and trained trees, and anything growing in them will take much longer to reach the stage you want that gives you the options (more branches, etc.) to be able to style with. Find those clubs - probably the best place to learn because you get to see how things are actually done - and start reading. I would NOT suggest a pine for a newbie, but you should learn about conifers (vs. deciduous or indoor tropicals) while you're at it as they play a major role in bonsai... www.evergreengardenworks.com. There is more to this than having a cute little tree in a pot that you trim on occasion! Good luck and come back with your questions (once you know what to ask about specifics).