I used to have a sh*tload of Hot Wheels when I was a youngster, and a complete town set that you could build and take apart. That was more than five years ago, and I'm pretty sure the majority of the cars and the other sets (including the town one) have been sold.
That's what I hate about growing up; I like a certain toy, then I don't play with it, then I get all nostalgic and want to use them again once I don't have it.
I have my carded collection because I used have something of a connection to Mattel. Long story, but I used to have friends on the inside until their [unconnected] legal team decided they wanted to sue me.
I wish I would have known to keep some of the ones I had as a youngster. I still remember some of the classics like 'the poison Pinto' from the ones I had.
I was never into keeping them packaged due to the whole zany track thing. But I had some very cool ones. A chaparral 2C, a Jag D-Type, a Charger Daytona. Had a huge collection of Ferraris and various muscle cars. Even at a young age, I was very much into the ones that were real cars and not made up.
You say they are you mom's(well, the bulk of the really collectible ones)? I'm no expert(for sure) but if those are originals and not re-releases, I'm guessing they are worth some serious cash. Any of those old advertising ones are the key.
I have some Hotwheels models too, but nothing special really...never really collected them, but as a child i did wanted to own all of those little machines and tracks and everything. Problem was money. Nowadays i don't know where all of those 1:84th scale models are, but i did collect 1:43 size models. Even a year ago i bought some. Those are quite expensive and very detailed, and the bodyshape is 100% correct. Handmade also.