All three letter .com domains are taken.

All of these 3ub domains can be purchased together for $35,000 USD.

3ub.com
3ub.org
3ub.net
3ub.biz
3ub.info
3ub.mobi
3ub.name
3ub.at
3ub.be
3ub.jp
3ub.nu
3ub.co.nz
3ub.tw
3ub.co.uk
3ub.us