I wondered about the free monitor if you buy test strips, but ideally you want to stick with the FSL since that's what you already have test strips for. Which is why I go back to my original comment of just buying a second FSL and having it as back up in the future. Strips cost ~$80 so it's not worth buying them for a different meter, when you can as you say buy a new FSL for $45. Some pharmacies have published deals in flyers, depending on the brand of meter, where you can get it for free if you by the strips, but I haven't seen those deals for FSL in a long while.
The other option as Wendy mentioned is to treat this like a vacation dose, maybe go down to 4u and wait until the meter arrives. If it were my own cat, and knowing his patterns, I might not suggest such a drop, but I don't know your cat, feeding patterns, and you have limited data which is where I am being more conservative in dropping down the dose.