Re: Low buck projects- Let's see 'em!
If you can use a router table or a jigsaw and a drill you can do it yourself, as Faster suggests. I did one for $100. Get a piece of plexi - an offcut will often suffice and is cheaper than having them cut a full sheet.
Dow 795 is the sealant of choice - it's what they use to hold the glass in office towers so it should hold a couple of square feet of plexi.
It's an easy job - cleaning the old sealant off the hatch is the slowest part - the mounting lip must be PERFECTLY clean.
I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.