I got into that Hot Wheels Red Line Club. The cars are pricey $20-35 each, but the resale on the is normally more than double if it's a limited edition with 30,000 or less.
Sometimes they do "rare" chase versions they randomly ship to some orders. Recently it was the 20th anniversary RLC custom Camaro with foil packaging that was the chase car. I got one of the chase versions and the initial prices on Ebay for chase versions were around $500 for a car that sold new for $25, since then the price settled to under $80 as the people realized how many chase packages were shipped out. I often just hold them and gift them in time to people unless it is one I really like. The pricest as far as I can recall that I gave away was the VW drag bus with the Candy Striper design I gifted to my little sister (she had a VW bug and a bus at one time), I see most of those listed at $100 -$300 still.
I'm hoping to see an RLC Focus RS in blue one day, they often have more detail, while than that first Night Burnerz release had the most detail so far, I could see an RLC release with detailed taillights, fog lights, spoiler and such, on some nice "real rider" wheels.