formula assistance if/than ??

i have four columns (we'll call them B,C,D,E). i need to come up with a formula (not code) in column F that says:

equal the cheapest price out of columns B-E on this row

then i need to fill them down. i don't know if i'm explaining this good enough, here's another example

column B1 has $1
column C1 has $2
column D1 has $3
column E1 has $4

i want F1 to equal the cheapest price, which would be equal to B1

thanks!!!