You see fry for sale on Aquabid and eBay all the time. Often there is a photo of the parents, along with the number of fry available. Usually from 10-30 fry. In other words, someone is either breaking up a drop of fry and selling them separately, or selling the entire drop from one female.
I used to buy fish this way frequently. My reasoning was that I could get a lot more fish for a lot less money. So instead of paying $50-100 for a trio or two of fish, I could get 20 fry for $30 or whatever. Fast forward a couple months and I have 20 adult fish. It also seems like fry are less fragile when it comes to shipping. And there’s generally a much higher likelihood they’ll survive the trip.
I’m not saying I would never do this again, but there are problems.
-You have no way to verify they in fact will grow up to look anything like the adult photos. I see a person on eBay using a stock photo of some really nice fish selling fry that are supposed to be from that line. But red flags are going up. By the time the fry are adult size (say 3-9 months later), you’ve probably already left positive feedback and there’s no way you can ever get your money back or leave negative feedback to warn others.
-The fry grow to maturity and you see the true genetic makeup. I once ordered some doubleswords (which are hard to find unless you attend IFGA auctions). The male breeder was featured in a photo and he looked PERFECT. The fish grew up and did not look good. They were doubleswords, but small, poorly shaped, short dorsals, etc. What I ended up doing was taking the 2 best males from this group, and I continue to see if this can be salvaged. But working with small, poorly shaped guppies isn’t the way to do it. Unless you want to spend 10 years on a project.
-Some breeders are selling the fry because they know darn well those fry won’t be their award-winning IFGA quality. I bought a drop from someone and they all appeared to just be struggling from day one. They were just weak fish. I didn’t even bother to raise them to adulthood, I just gave those away (and they weren’t cheap). When buying fish online, it involves a lot of issues. After all, you’re trying to ship fish in plastic bags filled with water 4000 miles across the country in difficult weather. It’s hard to ever say for sure if fish started out bad, had a rough trip, or aren’t doing well in your conditions. I hate turning something into an ordeal, so I cut my losses and move on.
-When you buy fry, they’re somebody else’s fish. You can never show them with the IFGA, because they weren’t born in your tanks. By the time they’re old enough to breed, have fry, and you raise those fry to show age, it may be a year later. (or more) I’ve purchased guppies in their prime, and had fry in my own tanks a few days later. Just by doing this, you’ve cut your time from purchasing to showing in half.
I would recommend buying fry if you’re not really trying to win awards. If you just want some ok, or possibly good fish, at a comparable price to a pet shop guppy (but likely higher quality), this option might be good. More than likely, you won’t end up with show quality fish from these. No matter HOW enticing the photos of the parents are. You’re better off spending a lot more money on a lot fewer fish from a reputable breeder.