They're used as oem fitment on some small cheap bikes, reputedly ok in the dry but not so good in the wet.
Generally speaking you gets what you pays for...
But if you want cheap I reckon you may struggle to find a better deal than these:
https://www.tyretectrading.co.uk/met...-17-front.html
https://www.tyretectrading.co.uk/met...0-17-rear.html