do you know a calculator where i can use a table and input data to find a line of best fit

A Ti-nspire CX CAS would be perfect (I use it myself) and is more popular than the Texas Instruments

Maybe a Texas lnstruments - 84 (not the silver edition or any version above, too powerful).

Wouldn't a spreadsheet like Excel work just as well??

Maybe this will work well ....

http://knowpapa.com/trend-line/