Put a removable pad on the stock first. You might just find what you need for fifty bucks or less. Then you can decide how much money you want to put into a permanent solution. A few hundred with an adjustable comb or thousands with a restock. Is this a gun which you have a reasonable chance of finding a higher stock to put on it? Some production guns have hundreds of new or used stocks available where some guns have zero to try. If yours is a zero is it worth several thousand dollars to restock? This is how money puts are dug every day.