As you can see, the floor doesn't quite match up with the rest of the kitchen, which is a mish mash of white/beige, black and butter yellow.

I'm hesitant to do vinyl because of the off-gassing, less eco-friendly qualities of it, but I've seen nice floors done with it on the cheap. What are some other temporary low-cost solutions (besides an area rug) that would work in this kitchen?

I would clean it, sand it, tape off a cool pattern using the existing grid as a guide, prime with a super bonding primer like XIM, and paint with one of the new-fangled waterborne alkyd paints. (Haven't tried them yet, but this would be a good chance to see how they perform.)

There are also fairly inexpensive vinyl plank floors that adhere to each other, creating a floating floor that doesn't need to be glued down. For the life of me, can't think of the name but maybe someone will know. Or, float a cheap laminate from Ikea...I have a few pieces in a hallway, heavily walked on for years, never installed properly, that look fine.