Sure, 20-30mm spacers have an rrp of £110+, but most online retailers sell them for significantly less and that's before you look for a discount code (which are pretty much always running) and get cashback (cashback sites and credit card).
So yes, I can get a set of new Eibach / H&R (probably the highest rated brands of spacers out there) for £70-£80 any day of the week, less if I wait for a particularly good offer.
Some people are impatient and willing to pay more or aren't particularly savvy, (un)fortunately I'm the opposite and don't see any reason to pay new prices for used items...
Evidence: