TL;DR: it’s a fair price, if you want more than one //e.
Seems to be worth the asking price, if you want both the //e computers and a TI-99. The manuals are a real treat. I would like to have them, but cannot bring myself to pay extra to buy them, so getting them included in the deal would be awesome.
Personally I think a fair classified ad price for a working //e is around $125-$150 with with two Disk II drives and an Apple Monitor II, as long as we are talking an enhanced //e, not ][e. Maybe worth a bit more than that if it has extra cards, manuals, software, etc. if they are not enhanced, then I would knock $15-20 off that price. My two cents. eBay will often show you higher prices than that. Every once in a while, Craigslist/OfferUp/etc will show you a better price than that. But $125-150 is about the going price. I think the lowest prices can be had by watching your local government, school & church auctions, garage sales, or by talking to your local computer recycler. They typically scrap any computer more than one generation past the current one and most would be happy to pass their vintage finds to collectors for a small finders fee. For instance, I paid $20 to a recycler for a working //c clone with joystick, external drive, and about 100 disks, some of which were very collectible original //e games (by that I mean not copies.) I would have given $20 for just a few of those disks alone.
The biggest problem with this method is that you have to wait a bit. That’s why I bought my first one from a CL ad for $150 (platinum //e, duodisk, Monitor II, 80col/64k card, software) I feel like I paid a fair price, by that I mean fair to both parties. I bought it from a guy (a member here: macdrone) who is more than generous to me when I need some obscure Apple/Mac part, so I was more than happy to pay what I considered full price to him.
That said, a deal can be found that is much better for the buyer using the method described above.