For those of you who don't the luxury or space to have your own grinder; how much do you pay to have your mower blades sharpened? I found this old gentleman that works on residential mowers and I asked if he could sharpen blades and he said the for $3 each he'll keep them sharp for me. Is this a good/fair price? He's only like a mile from my house so convenience is key. Thanks for your input.