I need Health Insurance to start an Internship in 9 days

Hi there! I am a 28 year old non-traditional college student who is starting an internship at Argonne National Laboratory on July 10. I had gone through the whole process and quickly had a ton of paperwork processed (this internship posting was very last minute and so everything has been a bit of a scramble), and then read in the job offer that I am required to have health insurance. I have been uninsured since I dropped off my parents' health plan when I turned 26, due largely to the prohibitive costs and the fact that the job I have for the majority of the year does not offer any health insurance.

I really do need to get this done as quickly as possible. I told HR at Argonne that I would try to have proof of insurance by Monday. At this point, I'm really looking at it as more of an expense than a true attempt at getting coverage, but I do need to make sure it meets the requirements. I'm pretty sure that any health plan will do, but I may have to wait until Monday morning to know for sure due to the fact that it is the weekend.

What are my options here? If I need to just kiss a bit of money goodbye and not get any real coverage, then I'm ok with that. If there's a way I can actually add to my quality of life and get real, decent coverage for a bit more money, then I'm willing to consider that too. I just need to have the process done very quickly, and I'm going to be dedicating my time this weekend to finishing this.