The easiest thing to do is search for replacement parts on the Internet. You can even pick up ramps or levels that are for a different cage, or take them out of a cheap cage, if you're willing to do some extra work to make them fit and stay in place. Thrift stores or other second-hand stores might be good places to try. If there is a ferret shelter in your area, they might have used cages for sale cheap, or be willing to help you fashion your own levels.

Easy ways to attach the ramps and levels involve using twisty-ties to find a good level and position (these are easy to remove afterwards; don't leave them on permanently) and then securing it with zip ties once you've got the set-up you want. It's fine to "test" your ramps/levels with the ferrets while using the twisty-ties; the worry is that they might decide to chew the soft plastic part off (bowel obstruction) leaving a wire behind (which they could poke themselves on). Use LOTS to insure that it won't fall off!

You want to avoid wood or any other porous surface. Basically, it makes clean-up a nightmare, and you'll never be able to really disinfect the platforms!

Use plastic or a wire frame to form your own levels. This can get complicated if you can't find something that already fits perfectly. What tools do you have available? I assume the goal is to make a *cheap* replacement for the ramps and levels, and not spend any money buying lots of tools just to make them. Remember that soft plastic should always be avoided, as ferrets can chew it off and get a bowel obstruction, and that you want something stiff that won't collapse anyway.

Coat any wire frame with something else--use covers made of cloth that you can swap out and wash with the other ferret bedding, or linoleum cut to size that you can wipe down easily. Be sure to cover any sharp edges or corners, too. You also have to be careful about small holes. A small gap is an easy place for a ferret to catch a toe or a foot when jumping between levels!

A good ramp can even be something as simple as a tube. My old ferret cage had a large plastic tube for a ramp between levels--they loved running through it! You can pick something like this up at any hardware store. Many use wires to hold them together, so be sure to cover any wires sticking out on the ends. Also, don't use anything with a soft plastic that they could chew off.

Finally, be sure that there are no big drops in the cage. Ferrets can be incredibly agile, but they can also be incredibly clumsy, especially when jumping up for a quick scratch! You don't want any space where the ferret can fall for more than one foot.

You can use hammocks to break those falls if you hang them well. In fact, hammocks could be used to make "levels" all by themselves!

Something to consider while building your new ramps and levels: Clean-up. This is probably the most annoying ferret chore. You want to make sure you'll have easy access to every level and ramp so that you can wipe them down.

A second thing to consider: Food, water, litter, and sleep. I don't know how many ferrets you have, but with four, I have two food&water stations in the cage, and two litter stations, and at least four sleeping spots--two hammocks, and sleep-sacks on the levels. If the ferrets decide to sleep on the top level, and the only litter box is on the bottom level, they may get lazy and just start using random levels. Similarly, you want to be sure that the ferrets can always make it to food and water easily, and you want more than one spot for food and water if you have a large cage, or if you have multiple ferrets.

A third thing to consider: Sick ferrets. If your ferret ever gets sick or has to have surgery, you'll want a cage where one level has litter, food, water, and sleeping spots. A sick ferret may not have enough energy to make it up the ramps! You don't need to keep your cage permanently set up with all of these on the bottom level, but you will want to be able to adjust the cage to make this sort of set-up possible.

If you end up deciding that replacing the broken ramps and levels is too much work, I recommend the Ferret Nation cage. It's the best cage I've found for my ferrets, and has a lot to recommend it! I've never had a part break, but it is possible to purchase replacement parts.