My HD in Hillsborough had a stash of 6ah and 4ah Ryobi 18v battery sets marked down in their clearance section for $99. There were about 3-4 left there.
Which is why I've stuck with Ryobi for most of my battery-powered tools. They've maintained the same battery configuration since I bought my first 18v drill set from them 25 years ago. They still worked fine when I gave my last blue Ryobi items to Bull City Woodshop a few months back.These battery tools are marketed like Computer Operating Systems with the Licensor deciding when the hardware you (merely the Licensee) paid all the money for is no longer compatible with their system and will, thus, no longer be supported - even as it works fine from your perspective.