Comic Books

I'm not sure where in Cape Coral you are, but I found 3 on this comic shop locator website: http://www.comicshoplocator.com/Home/1/1/57/575

You can also buy them online, but I find it much better to buy them in a store. Plus you get to support a local business! I'm not sure how old your grandson is, but our local comic shop has a section specifically for kids and my daughter heads straight for it when we go in. Just find a shop locally and ask.

I have occasionally bought harder to find ones online, but I prefer to do it in store.

Most big book stores have them. My son used to get them from Barnes and Noble.

Is there a Newbury Comics nearby? A lot of bookstores carry them too.

I read comics as a kid too! So many fun summer hours spent in a tent or under a tree, reading! I think anything that helps kids read and gives them a visual without them being attached to a screen is a great alternative. Superhero fantasies are fine, but there are other themes as well.

You could also encourage him to set up an exchange with other kids in the neighborhood, or see if the library will start up a "give a comic, take a comic" free exchange. Our library does it with magazines, and a local realtor set up a nice sitting area next to a coffee shop in a building he owns, and it's a free book exchange (mostly hardcover, some paperback). I wonder if the children's library where you are (or where he is) would set something up within eyesight of the librarian so things aren't too dogeared or over-handled.

Bookstores will carry common titles like Spiderman or Batman or the like. The comic shop you mention I am sure gets brand new comics weekly, it would be bad business if it didn't. Nearly every comic shop I have been into always has things like dollar bins or other marked down back issues, not just the high prices collectables.
Graphic novels are a great way to get a full story. They collect up say a years worth of monthly issues into one volume so you can read the whole story arch at once. They are also a great way to get older titles without paying high collector prices. Any book store will have a selection and the comic shop should have them as well.
My husband and I are both avid comic book readers/collectors. All 3 kids are following in our footsteps now too.
I would go to the comic book store and talk to the people working there. I have yet to meet a comic book store employee that wasn't more than happy to share all the ins and outs and recommend titles.

When my husband can't get them from a comic book store he orders them off of Amazon.