If you have an old outdoor rocking chair that is badly damaged, there may be a way to salvage a majority of the rocking chair, and just perform a few cheap fixes. You may be able to replace backs and slats with materials that you have in the garage, and you can even make cheap cushions to sit on. It might require being a little creative, but you will be surprised what can be done with spare materials that will return a broken or worn rocking chair to its prime. The following list of ideas is not meant to be a complete one, but to serve as a guide of how to devise fixes from materials that you already have available.
Fix 1: Cheap Seats and Backs
To make cheap and quick repairs to the seat or back of an outdoor rocking chair, replace them. Use a piece of 1/8-inch clear wood paneling or plywood and cut it to match the seat or back being replaced. You can use a thicker material, but you may have trouble getting it to conform to the curves of the surface being covered. The solution will probably not be as decorative as the original was, but it is a fast and cheap repair for a problem that could be expensive to take care of.
Fix 2: Plywood Rockers
You can build simple replacement rockers, even for an upholstered rocking chair. Mark out two identical arcs on a sheet of plywood and cut them out by connecting the tip of each end of the arc and cutting out the whole section. Turn the chair sideways, and attach the newly cut rockers with screws or tacks. It isn't a glorious fix, but on a chair with the rocker hidden underneath, plywood is a cheap way to make an immediate repair. This may not look very good on an open-base rocking chair, but for a closed base, it is often the easiest way to make accurate rockers.
Fix 3: Replacing Slats with Panels
Among outdoor furniture, rocking chairs may be the most susceptible to breakage and damage. If you have a chair and the slats are damaged, they can sometimes be fixed by ripping (cutting into strips along the grain of the wood) pieces out of some cheap material such as pieces of a privacy fence. Be creative and look at what materials you have on hand that could be used to replace the damaged parts, and you can probably avoid any cost at all.
Fix 4: Prevention Versus Repair
Any way you look at it, the very best way to save money on rocking chair repairs is to not have to make them at all. Keeping the cushion clean and the screws and bolts tight will only take a few minutes each month, but the payoff is a rocking chair that will last for years. If you notice a wobble, find out what has become loose, and tighten it. Wobbles are annoying at first, but the final result if they are not repaired is that the rocking chair will fall apart, and there isn't a cheap fix for that problem.