Design a garage to build inexpensively by constructing a one-car structure with an A-frame roof pitched to harmonize with your home's existing roof line. Steer clear of building a flat roof to save money, since you don't want to detract from your home's value. To build cheap, you will need to enclose the garage in exterior-grade masonry siding versus brick or cinder blocks. An inexpensive garage is more do-able by utilizing some recycled materials as well. For example, you might use windows someone removed from their home during a remodel.
Decide the exact perimeter of the garage and dig footings for a concrete pour. Hire a block mason to lay a short foundational wall around the perimeter. Have him construct the wall by using mortar to lay just two rows of cinder blocks directly on the concrete footings. This wall will support the wooden garage framing to be built. When foundational blocks are laid, be sure to leave a drive-in opening for the car at ground level. Put down 3 inches of gravel on top of the dirt to make an inexpensive floor.
Begin framing the walls and roof area by installing the first row of lumber around the cinder blocks. Use four-inch concrete nails to secure 2 x 8 boards (lying flat capping the block perimeter) to the blocks. Place metal flashing between the wood and the cinder blocks. Frame the garage walls with 2 x 8 lumber to include openings for windows and a walk-out door. Buy roof trusses or build your own rafters onsite with 2 x 8 lumber. Nail exterior masonry siding into place to cover the exterior. Secure siding with 4-inch stainless steel flat-head screws. Fit the pieces as tightly together at the seams as possible and caulk seams.
Install doors, windows and guttering next. Find a used garage door and used windows to install, if possible. Trade with friends or place an ad in a local paper. Refinish rough garage door and windows by sanding and painting before installing. Find a side door to install as a walk-out door on the garage. A side door is essential since a garage can catch fire and you'll need an escape route.
Install roofing and surrounding materials. Install 1/2-inch exterior-grade plywood to cover the roof and box in overhangs. Nail shingles into place. Hang guttering with 10-inch guttering nails. Install downspouts and lay pre-made concrete splashblocks. If you don't want to invest in downspouts and splashblocks, create an inexpensive way to carry off rain. A corrugated hose material attached to top guttering can serve as a downspout. Use a large barrel to catch the rain.
Hang the garage door on hinges after you've installed extra framing at the door opening to hold the weight of the door. Install tracking for garage doors, if you want to include it in your budget. Spend time to make the garage door either swing open easily on strong hinges or fine-tune the tracking so the door will rise easily. How well the garage door works will make using the garage much handier.