Freon Cost in Area

I was wondering if anyone can let me know the going rate charged per pound of Freon both R22 and 410a I was charged $25 per pound for 410 and told $50 per pound for R22. It seems really high as I can purchase 25 pounds of 410 on Amazon for $100

Thanks for input. Thinking i should keep some in the garage the next time I get service call and give it to the tech!

Also, who do you recommend for honest AC repair and install.