You might try Time Bomb on Garland.
When they buy stuff, it's generally old/trending comicbooks in good condition and good demand. However, Craig (the owner) does have a soft spot for older stuff (again, in good condition)... so that's a "Maybe" for your 70"s Spiderman swag. It's worth a try to see what they say, but no guarantees.
Yep, try the Time Bomb
Thanks! Your answer is awaiting moderation.