I actually had about 1500 Hot Wheels, all different and "real" cars/trucks only (no weird "concept" stuff). I had been buying them for about the last 12 years of so. About 3 weeks ago, I sold just about all of them to one guy. I didn't get much for them, but was happy to be rid of them at one time. Could have got more if I had doled them out in small bunches, but didn't want the hassle. I kept about 150 or so, mostly sets (eg. the 63 piece 2010 Delivery set which features auto/parts/aftermarket auto stuff logos - eg. Champion Spark Plugs, Hooker Headers, etc) and some rarer Limited pieces. I ceased buying the regular ones some time back.
The fun thing is that they are inexpensive, and you can amass a sizable colllection reasonably. The bad thing is what do you do with them after you have chased them down and bought them. I opted out.