Look online for rechargeable battery rebuilding services. I know they exist, I've had it done. Generally, the rebuild cost is about half the cost of replacement batteries. Your batteries are not available anymore because they are probably NiCad, and everybody has switched their technology to Li ion. If you cant find a place to get your batteries rebuilt, consider Ryobi tools. They are the most bang for your buck in that they are not very expensive, and will perform most drilling/ screwing tasks. They frequently have bundled tool sales of Ryobi products, whereby you get three or four tools in a tote bag for the price of two. Check Home Depot, Lowes, and Menards. These tools are almost always on sale at one of these stores.
65 yr old carpenter. Bought a complete set of Ryobi for my son as a bundled package.