What to do now? Well, let's start off with what type of hamster you are going to get.
I will always say get a Syrian hamster. Why? There are a lot of reasons. They are small, and stay small. Also, they have a shiny golden furry coat that I just love. And, they don't have to be with another hamster. In fact, they will fight to their death with that hamster, just like male betta fish do. So, you don't need as big of a cage. If you can't find the name "Syrian hamster" at the pet store, look for other names like "common hamster" or "Golden hamster" or "Teddy Bear Hamster". Those are also very common names for Syrian hamsters. Although some people get confused, Teddy Bear Hamsters and Syrian hamsters are the same exact thing.
If you want more than one hamster, I would say get a Dwarf hamsters. They have to be together.
Next, let's talk about the cage. There is only ONE cage that I will ever recommend, and that is a plain wire cage, with a plastic bottom. Those allow air to flow through, and there is no way that the hamster could get stuck.
A very common cage is a cage that has many plastic tubes for the hamster to go through. Don't get that type of cage. Even if you have a dwarf hamster, your hamster will get stuck inside the tubes, which can be fatal. You would hate to come home to a hamster that passed away in a plastic tube, even after I told you not to get that kind of cage, wouldn't you?
Also, many people have thought of getting an aquarium for their hamster. People have many different reasons why, but the most common reason is "I don't want to smell my hamster". Let me set this straight for the billionth time. Hamsters don't just start smelling by themselves. This is one exception, and that is when the female is in heat. So if you want to avoid that, just get a male. But just assuming that your hamster is a male, or not in heat, hamsters don't smell themselves. They smell when their cage is not clean. So if you "smell" your hamster, either your smelling yourself, or you need to clean the cage. But the reason I am truly against aquariums, is because they don't allow air to flow through, which is not good for the hamster.
So, just because the cage looks cool, or because you don't want to smell the hamster, doesn't mean that the cage is okay. You need to choose it based on what is best for your hamster.
Also, we need to talk about water. The water either needs to be clean tap water, or it needs to be dechlorinated. It also needs to be in a bottle, not in a dish. If it's in a dish, it will not only get the fur coat wet, but also will get the bedding wet.
Have fun picking out your little puff-ball!