You have got a wonderful example of S&W artistry in revolvers. I love the .22 LR revolvers made by S&W. I've had some really nice M-17's. I always wanted to own a 4" M-48. Never got around to buying one.
Once upon a time I chanced to read some articles on .22 LR handguns by Mike Melick. He absolutely doted on the M-18. I had a Browning Challenger II that was hit or miss on feeding/firing. So... at the local Ace Hardware Store (how about that!!!) I traded it to the owner for a brand new S&W M-18. What a revelation. That thing would really go! Since then I've let it and four more go through my hands. Currently I have one that I bought in 2004 from a retired Marine friend. It is positively the most accurate easy to shoot .22 LR handgun I've ever owned or fired. Last year I was helping a church member put up a irrigation pivot system. We took that little revolver and had a big time bouncing aluminum drink cans double-action out to maybe 30-40 yds. I fired one cylinder load against a peanut trailer that was 55 long steps from the truck. All six rounds hit into less than 5 inches.
You hold on to that M-18... S&W isn't making that little jewel any more. As far as price, forgetaboutit!!! You never spend to much. You just buy to early. When I bought mine, $350 was almost to high. Now... five years later... it feels real good. Buy some ammo, grab your S&W M-18 and head for the range. Let everyone figure out why your smiling!