Thank you for the feedback. The key addition that you get with the Explorer is access to bulk prices and bigger maps, but I probably don't say that clearly enough... you can actually buy and make maps with a free account.
Even after reading this and now knowing that you can make and buy free maps with a free account, it's still really not clear from your website that is the case.
My recommendation: make it as stupidly easily possible to buy a single map whenever you want, with the option for no account at all (and make it clear you can do that through your website).
I could conceivably see myself using this, the output looks really nice. But as soon as I need to sign up for an account, even if it's free..... ugh :-/
Make it easy for people like me who might be on the fence to give you my money :)
Hmm, I suspect you are right, thank you for the feedback. I think my customers will be business owners with some technical expertise (you need to at least understand what a transparent PNG is, and be able to paste it on your background), but I don't want to discourage end customers. I need to think about enabling map creation without accounts. I am requiring accounts now because you'll have to design a theme before you make your map (star colors, labels, fonts, etc) and I am assuming you'll want that to be saved. But I could make it optional...
You could also build up a temporary pseudo-account based on an anonymous user's session that could optionally be upgraded to a permanent account with an ID and password at any time.
This is common with e-commerce sites. Many don't require you to make an account to add items to your shopping cart or even to check out. But if you want to make an account, they make it super easy prefilling info they already have, and they certainly won't make you lose what's in your cart.
Another customer segment you could go after: I generated the star map from the day/time/location of my wedding, and themed the colors to match the wedding colors. My wife thought it was a great idea to print + frame it.