Yes. When you are financially hard up, you should say "I know XYZ well". If a project using XYZ materializes, you brew a huge pot of coffee, and spend the next 24 hours internalizing everything you can find on the web (and in the bookstore, if you are so inclined) using XYZ.
If your immediate inclination is to think that this is lying or misleading, hear me out - it's not so cut and dry. In a conversation, you don't know what kind of experience level the other party considers "well" vs. "not so well"
- e.g. some people think that "wrote my own gem" in Rails mean expert, whereas others would be more skeptical and say that there really are very few experts out there, and someone on Rails core team qualifies, but that's about it.
So, in your situation, especially if you are hard up for cash, why not bet your skills more?
