Never let tenants do any repairs themselves. Ever. 99.9999% percent of the time they'll screw up the repair.
If you have tenants pay for repairs under $100, they either will:
1) try to fix it themselves (and cost you more later with a bad repair)
2) not tell you about the repair, thus costing you more later
(a tiny $20 toilet repair could turn into a pricey repair for you)
3) they'll only tell you about the repair after it's been broken a while and now is an urgent need. Example: the hot water heater has been leaking a little for months, but they didn't tell you since they didn't want to pay... now it's GUSHING water... your hard wood floor/carpet is ruined... and the water heater has to be replaced altogether. Or, there was a small ceiling leak from a shower or toilet. Tenant didn't want to pay before so they didn't tell you. Now there is a huge leak, and you have more than a patch job to do... plus, potentially, mold in the drywall.
Even if you don't make tenants pay for repairs, they still might not call you. A repair means they are inconvenienced with maintenance people (and you) in their home. And, they don't like that. So, they might just live with the dripping sinks, leaky toilet, leaky ceiling, and more.
Tenants are lazy. My roommates are lazy, and I live here. It's a pain to get them to even replace a light bulb. You think they would pay for a repair? Never.