The perfect first fruit tree, apple trees will bear fruit with little effort, although that doesn't mean there aren't factors worth considering. Firstly, pollination is important as without a pollination partner many apple trees will not produce fruit! Hence, if you are in a isolated location it's essential you buy a compatible tree such as a crabapple - the best pollinator around.
Secondly, rootstocks such as M26, M27 and MM106 determine the size of your tree with dwarfing rootstocks producing smaller trees. Thus, if your garden is small a dwarfing rootstock is a must.
Lastly, if you are to buy multiple trees, don't buy multiple trees in the same fruiting period, or you'll end up with a glut. Buy an apple tree from each and you'll have fresh apples for longer