Sorry, I have to disagree. Yes, it is awesome that you want to give this dog a good home, but it is coming from a BYB- and it is probably free because the dog is leftover and the BYB wants to get rid of it. So in a way you are helping and encouraging the BYB to keep on doing what he/she is doing.
And if you can't even pay for food ALL by YOURSELF, which, IMO is the smallest cost of owning a dog, then maybe you are not ready for YOUR OWN dog. Especially one that comes from a BYB and could be associated with all kind of vet costs. Nobody here was disappointed what happened with your dogs before, but at least I can say that I will be mad if you don't learn from mistakes. What happened with your dogs should have been THE experience that you own your OWN dog when you are financially able to.
How about just fostering for a shelter until you get to move out, finish school, and are able to pay for YOUR dog's bills?
I agree with everything above, except the part in bold. I don't think taking a free ex-breeder from a BYB will encourage them that much more. Buying a puppy and putting money in their pocket, yes. Taking a free ex-breeder off them, no. I have 4 ex-breeder dachshunds from a puppymill size BYB (hundreds upon hundreds of dachshunds), and all were free. If I hadn't taken them, they would've ended up in the pound. How I know is because it's what she's done for all the years I've known her, and continues to do till this day. So a lot of BYB's really don't care.
Now, having worked for a long, LONG time (many years) with dachshund backyard breeders, and taking in 'leftovers' and fostering, fixing, and re-homing them, I will say now that you DO NOT need this dog. You are going to get yourself into a lot more than you'll probably be able to handle.
For one, BYB breeder dachshunds almost always come with teeth problems. I have 4, all from diff. lines, and all had infected teeth rotting out of their mouths. Mattie lost all his teeth, Rosie is only 2 and lost 13, Gracie lost 6 or 7, and Callie lost 10. Rosie, Gracie and Callie are all due back to get more teeth pulled in a couple months, which will be several hundred dollars for all. I have fostered and re-homed countless dachshunds in the past, and this was always the case.
So unless you are financially ready, right this moment, to spend a couple hundred dollars, or more, just to have teeth clean, pulled, and antibiotics to follow up with, then you aren't ready. This is on top of the dog needing to be spayed, possibly brought UTD on vaccinations, plus the routine vet exam that this dog will seriously need the day you bring it home. There's also the monthly cost of heartworm preventative.
This is also a female. You have no idea what her lines are, or what will come in the future. Two of my BYB females have tumors, and Rosie is only 2 years old. Rosie came with horrible allergies, Callie came with elbow dysplasia, and Gracie came with liver problems. Rosie requires medication for the rest of her life, and is about to be put on medication that will cost $200 a month. Would you be able to afford that? Gracie is on medication that cost $40 a month, plus special food cause of her liver. Would you be able to afford that?
Are you ready, financially, to deal with this if you get this dog and these things come up?
Dachshunds, coming from BYB's, are not easy to house-train. It took me a lot of time and consistency to house-train them, and then sometimes there are still mistakes. Will your mother allow this? Because according to you, in another thread just a few days ago, she is threatening to throw your cat outside for not using the litterbox. So I have my doubts on how this dog will be handled if, and WHEN, it pee's in your mother's house.
I think you need to wait, get a job, save up money, and be able to financially take care of a dog BEFORE you go get one.