Do you have the regular drill and the impact driver drill? If so, another option is to pick up a new Ryobi tool (not a drill) that you want, and it will come with a battery or 2 and a charger that you can now use with your blue Ryobi existing tools. Even something like the Ryobi jobsite radio with a battery/charger. I sometimes see them for about $45 on sale.
If the existing drills have been lightly used, that would even be more of an attractive option. But if they've been beat on pretty hard, then sure just buy new drills. There is a great kit for $199 that comes with impact driver, regular drill, circular saw, reciprocating saw, light, multi-tool, and 2 batteries/charger. It's sometimes on sale for $199.