First of all it's important what you need. If you wanna a 3d printer under 1000, you can try rep rap printer. But it's little bit difficult to combine it. Because you're gonna try design a printer and collect parts. Some parts doesn't fit your design, gonna read tons of datasheet and documentation etc.-It all depends on your abilities,I made it one- Or you can buy from any manufacturer. But I want you to know, if you want big build plate(300mmx300mm or +), direct extruder, heated bed, etc. kind of features, they will push your budget.