I use the cheapest ones from Decathlon (clear) which are around £8 a pair and have been great. I bought several pairs are future spares as at the price they are almost disposable.
As above, i also have several different spare lenses for a few types of DHB glasses (they seemed to change the lense shape every time i bought a pair?) which you can have if they match your ones.
For sunglasses i have 2 pairs of ‘nice’ Giro glasses that my LBS sold me at cost when they stopped stocking them. £25 a pair instead of c.£100. Just goes to show the mark up on these things which is why i don’t buy expensive sunglasses anymore.