I'm a little confused, Nasridine. First you ask about "go in for one" but then you give an example with "I'm in for one" (without "go"). The verb in the first example is "go in" and it's "am" in the second one (as Joelline said).
"I'm in for one" means "I'm about to experience one." For example, "I'm in for a surprise" means "I'm about to be surprised by something." "I'm in for a great year" means "I'm about to have a great year." As Joelline said, though, it doesn't really make sense after "This is a super deal."
Do you have more context?