We had this one for a while and had no complaints:
https://www.amazon.com/Prevue-Products-Wrought-F040-31-Inch/dp/B00176F5L0
Funny enough, this PetCo cage: https://www.petco.com/shop/en/petcostore/product/you-and-me-finch-rectangle-flight-cage is actually a great minimum for a bonded pair of budgies, especially if they get lots of outside cage time, and it's a good quality. Unfortunately once you get bigger than this, the cages won't fit well on top of a bookshelf. So if you want a large flight cage, you'll have to make room.
Pervue and Mcage are brands that have been around for a while and usually have decent quality for how cheap they are. Lots of people here have used one of these two but I have no personal experience with either. You can try checking local bird stores to see if they carry some in stock you can inspect before buying.
Some of the best toys I've gotten for my birds were from local bird stores. I literally have purchased toys from stores that I absolutely can't find anywhere else online. I suspect the store owners make some to sell.
You can try buying toys from https://www.birdsafestore.com/X-SmallBirdToys, they also sell parts so you can assemble your own toys or you can try buying custom toys from Etsy: https://www.etsy.com/ie/search?q=parrot%20toys but beware, there's a scam going around Etsy where people will advertise stuff as handmade then order the thing for you from Amazon or Wish and profit the difference.
A decent alternative to Amazon is Chewy, however the quality of what you get will vary, even if it's a well trusted brand. Last time I ordered from Chewy, the stuff I got look like it was used and returned.
I wouldn't do more than two in a cage that size. Zebra finches tend to be rather pushy, so even a moderate-sized flight cage could be too small for all of them. I might be too late, but I don't recommend vision cages. They are a horrible pain to clean, since you have to take the whole bottom off. A cage like this is much better, and costs about the same.
Link as promised. The vines in her cage are all from the dollar store, I only buy one or two perches or toys at a time. I make a lot of her stuff.
This cage, or something similar is usually a lot of bang for your buck. It gets suggested a lot. Sometimes you can find it cheaper on other sites.
$24 difference between the two. the ebay one has about a 6"L x 4"W x 16"H difference less than the Prevue
which would you choose? im just sitting here waiting to purchase one of the two lol