Good advice from 72challenger. Please take into consideration the current state of the economy.
A few years back, I was in a phase of collecting Franklin and Danbury Mint vehicles. There are some pieces that have appreciated in value from their original MSRP of $120 and some that still command close to MSRP. But there are also pieces that have depreciated markedly.
Factors to be mindful of are: condition ~ (please be completely honest when describing, noting any flaws, scratches, chips, cracks, etc.)
packaging ~ original box, styrofoam insert, accessories, hang tag (Franklin Mint), title (Danbury Mint), other documents.
Has the piece been displayed? If so, out in the open or in a sealed display? (dust is the enemy!)
I have bought loose (no box) FM and DM cars and I've bought mint, boxed cars. It is sometimes about availability (rarity) of a piece and price is also a factor, of course.
Do some pricing research by looking on ebay. Check for as many examples of each piece you have so you will get a range.
In closing, I would be interested to see a list of the models you have. Just click on my HT name and the drop down box will offer the option to send me a personal message (PM) or you can email me. Thank you.
I hope this information is helpful. Good luck!