Comment by oliwarner

Maybe. At the very budget end, I was really thinking you take the £150 worth of sensors and motors (when bought new) to make something better.

We just got a second hand Ultenic T10. The 2021 model is commonly available for £40 used. It tangles a couple of times a week and its battery will probably need replacing eventually, but it maps well and empties itself. At that sort of featureset, just a brain transplant to get it offline would be a welcome upgrade.