Mike Dyson ( now
https://www.inmotionproducts.com/ ) does some Ozzo brand "washable gel mitts" which have a good layer of padding
They are um about 12.50 which is a good price for a quality product. Excellent pad, last a good long time.
Cheap mitts are often available from Tchibo/Aldi/Lidl. I had a pair from Tchibo which had good padding but they fell to bits after a couple of months. Cheap though.
I had a pair of specialized gel mitts, which cost me 25 quid(!) the padding was excellent but the build quality was rubbish, again they fell to bits after a few months. I hope the recent design changes have not removed too much pad.
Another expensive option were the Assos mitts. I don't remember which model, I got them from Ribble Cycles. They had some advantages. They were extremely comfortable. Their wicking performance was astonishing. But they fell down in an important way. The pad was thin and seemed unlikely to absorb
any road shock whatsoever. If they had a good pad I would prefer these, regardless of the price
On the topic of numb hands in general, I find getting bike fit right is more important than mitts. So that could be a lot more expensive than you had in mind