I use the simple two roller, sheet metal, screwed-to-plywood version that you're probably talking about ("cereal killer" where I bought it). I mostly brew session beers, so not a TON grain, but it works well enough for me, and was around $100. ...I can't say I've heard of a HBS charging to mill grain, though. IMO, that sort of sucks. It can't make them THAT much money, and is a definite way to annoy customers. More on reddit.com

I’ve been brewing for …13 years? Damn that sucks to say. Anyway I use a corona mill I bought for $30 and use a power drill. I get excellent efficiency. Good luck. Edit Premium Quality Cast Iron Corn Grinder For Wheat Grains Or Use As A Nut Mill https://a.co/d/9NtW5JU the exact one I use, bought 8 years ago. More on reddit.com

The cereal killer is often available for as low as $89 or infrequently $79 and is $100-110 regular price. It works well. I have one and have no complaints. My batch sizes are usually 2.75 gal and/or I make low gravity beers. I expect it to last maybe a decade. If I made 10-gallons or beers with huge grain bills, perhaps it only lasts a few years and it may be worth buying something really heavy duty like a Monster Mill. More on reddit.com

I’ve been grinding my own flour for 22 years now. Love the freshness of the flour. Here’s a list of my experience: grain lasts a LOT longer than already ground flour. freshness is unparalleled the KitchenAid Grain Mill attachment seriously sucks, avoid at all costs unless you want it for making cream of wheat (very coarse grind) my first mill was a KitchenMill, good but didn’t last as long as I thought it should’ve. second mill I got was the NutriMill Harvest Grain Mill, absolutely excellent and decently priced, watch for sales at big holidays. They seriously stand behind their products. Their customer service is outstanding. No I’m not getting paid for this, hahah. I buy grain in 25 lb bags from Amazon nowadays since grain is more scarce than it used to be in New Mexico. I buy Hard Red Spring Wheat for its higher gluten content for breads, and buy Soft White Winter Wheat for making tortillas. More on reddit.com