does it take shock's or struts and what's the difference

Blazer is equipped with conventional shock absorbers - not struts .. IF shock absorbers are original - they definitely need to be replaced! Recommend hands-on testing / inspection plus test drive - by qualified personnel.

go to rockauto.com and put your vehicle info in,select suspension,then select shock.it will give you the info for the front and rear with a wide variety and several brands to choose from, at unbeatable prices if that's what is squeaking,which might not be the shocks,possible ball joints!