How much should I save for my breast implants?

It sounds like you have a good “levelheaded” approach;  best not to go into debt… Despite FDA recommendations, some patients under the age of 22 benefit from the use of silicone gel breast implants and I utilize them frequently for patients of all ages.  When it comes to costs of surgery, there may be many “variables” involved. The specific surgeon's credentials/experience level (or lack thereof), the specific geographic area you are looking at, the different operations available, the location of the procedure (quality of surgery facility), type/quality of anesthesia provider,  type of breast implants… are some of the potential variables involved.  You will find some average cost of surgery listed on this website and on individual plastic surgeons' websites as well.
In regards to outcome of the planned procedure, more important than costs of the procedures will be careful selection of your plastic surgeon. I would suggest starting with the American Society of Plastic Surgery and/or the Aesthetic Society of Plastic Surgery to obtain a list of well experienced board-certified plastic surgeons.
Then, I would suggest you visit a few surgeons whose practices concentrate on aesthetic surgery. Ask to see lots of examples of their work and preferably speak/see patients who have had similar procedures done.
Be very careful with your decision-making. You will find, while doing your due diligence, that there are many different “specialties” who will offer their services to you; again, I strongly recommend you concentrate on surgeons certified by the American Board of Plastic Surgery.
Again, I would also suggest that you do not base your selection of plastic surgeon primarily on costs of surgery; keep in mind that revisionary surgery may be more costly in many ways.  Best wishes  for a happy new year.

Thank you for your question. I would discourage going too large as you are only 5'1" and too large makes you look disproportionate, and "believable" is a good thing. With your low weight, you do not need a large implant. I have seen many girls with small breasts go to a large implant from a "B" cup, and develop stretch marks on their breasts, and now have to hide them because they do not like them, and the opposite of their goal is realized. They look better in clothes, worse with a bra only or bikini...not their goal. Talk with your board certified plastic surgeon, and ask him/her how large you can go and keep your stretch mark risk to a minimum. Too large can also decrease nipple sensation, another negative so make your decisions very carefully, a lot is at stake. I hope this helps!

Thank you for your question.Realself provides data for the average cost of breast augmentation in your geographic area.  Price usually varies surgeon to surgeon.

To be sure, see two or more experienced,
board-certified Plastic Surgeons for a complete evaluation to make sure you are
a good candidate and that it is safe for you to have surgery.

I hope this helps.