Only a few companies are now using BCD, it started from UM, their Mest Mk2 often on sales for $1k, also Mext for $1k or even less. Rest of the UM line with BCD are really good, such as Mason or Mentor, but they are at least $3k. Another company is EE, unfortunately, all of their IEMs with BCD are priced above $3k, and even with sales and discount, they are way above your budget. One more US company Fir Audio has their recent line all comes with BCD, they are all above $1k, maybe you can check their cheapest option.
UM started with BCD covers 500hz above, and EE as second introduce all frequency BCD, while Fir Audio has BCD only covers the bass. However, UM's latest BCD on Multiverse Mentor covers all frequency range.
There are some small Chifi companies comes with some kind of BCD, such as Raptgo Hook-X's piezo driver, they are not as powerful or impactful as the above mentioned three companies.