I'd like to know if Intel processor Core i5 4690 Box Haswell comes with thermal paste or do I have to purchase it separately?
the stock cooler comes with it pre applied, this covers 1 installation, if you remove the cooler you will need more, if you use an aftermarket cooler it may or may not come with either a tube or preapplied
Yes, but it couldn't hurt to have some extra laying around anyway.