CRE Analyst - What I need to know for Excel

I am trying to land a position in Commercial Real Estate -- Hotels to be precise, but i'm not gonna be picky for the short-term.

I have been trying to re acquaint myself with Excel again: so far i'm working on PivotTable, IF and Vlookups.
I understand the likes of BIWS, WSP, etc but I have a few questions:

1. Can I get BIWS 2nd hand from someone?

2. Alternatively, can I just gather what I need to know from Youtube's ExcelisFun Channel? If so, what videos should I concentrate on?

3. Can you recommend the top Excel functions I should know in regards to this subject?

4. Where can I teach myself to build DCFs and valuate CRE? What other investment formulas should I know?

I do not have the financial capacity at the moment to pay for the expensive programs such as BIWS.

Thanks a lot guys!