just go for some of the old models.
if we take canon for instant (you can do it with other brands as well, but im not that famililer to their names etc) you can see that the 500D just came out, which means that the 450D is lowered a lot in price, sometimes you can be lucky to find that, and down to the 350, very cheap because their out of production and the shops just need to sell them, to replace with a new model.
and then you can allways buy better optics in the future :).