I'm with iwanttofish on this one. $200 is a very generous offer. However, that amount is probably illegal.
I'll take a guess at a less subtle version of what iwanttofish said about your offer being taken wrong: That's the kind of offer an undercover officer would make to see if anyone would take an offer to "guide" without a license.
Hopefully, one of our Ifish Guides can confirm my "guess," but I think I'm pretty close to accurate. $200 and using the boat owners gear sounds like "guiding" to me, which requires a license.
If you're sincerely just looking open seats, check back in early May.
If you're an undercover cop, then "<insert four letter word here> you !"