It really depends on the individual piece -- material(s) used and complexity of design. Simple dresses start at $1200+ and more elaborate dresses are priced around $4000++. Jackets start around $3500 and go up to $6000++.
Thinner, simpler tweed jackets are somewhere around $5000 but thicker and more elaborate jackets have been priced really high, as in $9000+ these days. If you are in US, you are very likely to find most on sale. One downside is, if you wear the smallest sizes, it would be a lot harder to find your sizes during the sales.