YABU. Your friend was not being stingy. It's her internet, and she pays for it, so it's her prerogative to say no.
Once again though, we have people saying people are tight/ mean/ stingy/ unreasonable/ awkward/uptight etc etc, because they don't want to do something they would do. I get sick of people being lambasted by posters, because they have a different way of dealing with things, and a different set of standards. Are you people like this with your friends? 
I have to say the OP sounds a bit entitled, and from her posts on here, I can see why her friend doesn't want to share her wifi. I am willing to bet this isn't the first time she has asked for stuff for free. I know a few people like this actually.
I would absolutely say no to most people who asked for my wifi password, because I pay for it, it's mine, and I absolutely have the right to say no. Any friend who can't be arsed with me anymore, for being so 'stingy,' is quite welcome to jog on.
@pickachew
Hang on. If your home Internet has been cut off and your phone Internet isn't working, how the hell did you start this thread? Or is it all sorted now, anyhow>
PMSL just noticed this!!!
Maybe the OP can enlighten us?
How are you posting @CadgingCarol with no internet?
I am dying to know! 🤔