I would never take a horse without a current coggins. You all DO know what happens if a horse happens to test positive, don't you?
I would never invest feelings, time or money on a horse until I KNEW it wasn't going to be euthanized for this disease.
Anyhow, a horse cannot cross state lines, or be boarded anywhere without a current coggins...which is usually asked for by the facility's owners.... BEFORE IT goes there
So if the OP is boarding at a facility other than her own farm, she will need a coggins.
And if you take that horse across state lines without a coggins, or try to....you may find yourself in a heap of legal trouble.
I agree with tblvr....sounds like the owner is in an awfully big hurry to sell this horse, rather than paying for the small fee it costs to have a coggins drawn, and waiting days/weeks it takes for the test results....