How Can An Average Joe Like Me Be Able To Silk Screen T-Shirts?
So, I Want To Make T-Shirts For My Band. I Did Some Youtubing About Silk Screening, And Kind Of Understand The Process. But Can I Get Some Advice On Where And How To Get The Supplies For It? I Only Have Limited Money And Want To Do This Cost Effectivily.

Silk screening and screen printing can be costly.
But if you are looking to do a simple one color print, I would suggest going to the local craft store. I know Hobby Lobby has an at home screen printing kit.

How To Open An Online Clothing Store?
I Would Really Like To Open An Online Clothing Store...But I Really Have No Clue Where To Start. How Do I Acquire Clothing To Sell? Are There Websites Available That Get Rid Of Clothing That Is An Overstock So In Turn I Can Sell It? Please Help!!!

Online clothing store for used or new clothes?

I know people have their online clothing business where they sell used, vintage clothing. You can find some amazing vintage used clothing etc. at your look thrift stores at incredible prices and sell those to your online audience.

If you are looking for new clothes then you can try eBay wholesale lots. It depends what kind of clothes you want to sell.