Wedding Dress Alterations

You cannot alter any dress that significantly without basically rebuilding it. The cost may depend on your area, but it could easily push $800 to essentially take a dress apart and remake it.

I am roughly the same size as you and I wouldn't buy a dress that big. The $800 you saved will go directly back into the dress for alterations, and it'll be a lot! Size 10 chest area will need to be completely re-worked to make it fit your chest area size. You should get a 2 or 4 at most.

I would contact the dress salon and ask if they offer alterations for dresses not purchased through them. If so, then ask to speak with the alternations department to see if this is something that can be done.

I know that 4-6" you mentioned doesn't seem like a lot, but I think in wedding dress land that is a lot.

Good Luck!

The general rule of thumb is 1-2 sizes, and definitely no more than 4. The more extensive alterations you need, the more expensive they are, and altering a size 10 to a size 0 would require a total rebuild and would likely entirely eat up that $800 savings.

If you like the idea of finding a bargain, I suggest checking out sites like StillWhite, Poshmark, PreownedWeddingDresses.com, Tradesy, and others in addition to eBay. I got my dress on StillWhite for $400 plus shipping (new it would have been $2100-$2400) and it fits me without any alterations needed.

Also keep in mind your "street size" is likely different than the "label size" of most bridal dresses. I'm a street size 6 and my dress is a designer label size 12. Most of the dresses I tried on in bridal shops were an 8 or 10. My MOH had to go up a size for her bridesmaids dress as well. If you are a street size 0P, then there is a chance a label size 10 is closer to a street size 6, which would be about 3 sizes off, so within the realm of what is possible with alterations but likely still expensive. One of the reasons I loved shopping on StillWhite is that dresses are sorted by "street size" so it makes searching easier, but they show you both the street size and label size. I'd at least go on there and search for that dress (or at least the designer) to see how much variation there is between the street size and label size. Also many brides post their exact measurements which is super helpful, and how I found a dress that fit me without any alterations needed. Some designers also have size charts on their website (but I find most of the higher end designers don't provide that info and instead insist you go to a shop and try on dresses in person).

I'd probably pass on buying a size 10 and search for dresses that are a street size 0-4 as options.