This is what a contractor does when he doesn't want the job because it's basically too small and would be more of an annoyance than anything worth doing. Bid an outrageous amount and then if the client says "yes" at least you're making some money.
He's probably got a backlog of large jobs he can make more money on. So if he's going to come out and do outlet installation on one house, he's going to bid an amount that is worth delaying other work.
For small/simple household jobs, you should call a handyman not a trade contractor.
FWIW I paid about $100 an outlet recently (as part of a much larger project). Yes you can get 99 cent receptacles at Home Depot, yes they will be crap (residential grade) and likely not up to code. NEC requires all circuits in the kitchen and bathroom be GFCI protected, and all kitchen outlets to also be tamper resistant. A GFCI, non-TR receptacle costs bout $15 at Home Depot, and again you're talking bargain basement units that a professional electrician may not want to install for risk of having to eat the cost of a return visit. Commercial and hospital grade outlets both cost more ($30+, $50+ respectively for tamper resistant GFCI). The outlets with USB A+C ports start at around $60 per.
In some jurisdictions you may be able to get away with one GFCI outlet per circuit, but then you're paying for their time to map out which circuits are which.
He's probably got a backlog of large jobs he can make more money on. So if he's going to come out and do outlet installation on one house, he's going to bid an amount that is worth delaying other work.
For small/simple household jobs, you should call a handyman not a trade contractor.