First off i do use Google earth plus but it do not believe it is required for the program i use. I only got it to save time entering waypoints from my gps when i go scouting. it it was either 20 or 40 for a year.
OK here goes, this is a reply that i already gave to a few through pm's:
i got the overlays at
www.usgsquads.com, once there scroll down and on the lower right corner you will see the place to download it for google earth. once you download it there are a few ways to use it. you can either click your state - that will put a bunch of i's in circles (symbol for information) each symbol is aUSGS topo map area. you click the i you want once anda balloon will pop up and you can download the map to your desk top. second way is click the topo overlay box and you can see an over lay in the area you are looking at on google earth. make sure when you first download it and use it that onlythe boxes you will be using are checked. i removed all states that i dont need so basically i only have michigan on my computer. there are some pop up windows you can get rid of by unclicking the warning and instructions boxes. It is really really easy to use. the instruction box gives you a brief run down of exactly what you want to do.
About taking the maps to Costco or Sams. you will have to download the map to your computer then convert the file to a jpg. It is really easy if you have never done it. I used a program called Lviewpro. All you do is open lviewpro, open the map, click save as, then name it and under were you name it change it from .tif to .jpg and you are done. fedex kinkos said they would do a colored 18x24 map for me for 25.00 and sams did a 20 x 30 color through 1 hour photo for 11.00 + tax. I got it matte and put it behind a poster frame with a plastic cover and i can write on it with dry erase markers. If you get stuck or need more help let me know.