i know this gets asked probably all the time but I just wanted a straight answer. What are the chances of getting pregnant while using a condom and taking birth control pills regularly and only having sex once during that month's span.

Slim to none, especially if the condoms have spermicide in them.

Read this About 14 out of 100 women who use condoms will become pregnant during the first year of typical use. Only two women will become pregnant with perfect use. More protection against pregnancy is possible if condoms are used with a spermicide such as a foam, jelly, suppository, film, or if combined with another birth control method such as the pill, patch, Depo shot, etc. The Pill is one of the most effective reversible methods of birth control available. Of every 100 women who use the Pill, only five will become pregnant during the first year of typical use. Fewer than one will become pregnant with perfect use. Birth control pills work best if taken at about the same time every day. Pregnancy can happen if an error is made in using the Pill — especially if 1) pills are started too late in the cycle, 2) two or more pills are missed in a row, 3) pills are taken in the wrong order. In cases like these, a back-up method such as a condom, would decrease the probability of pregnancy. The birth control pill does not offer any protection from STD’s. Latex and female condoms can also help prevent the transmission of STD’s such as HIV.