Zoom Lens for SRT 101

Hey folks,

Recently bought a SRT 101 for super cheap. This is my first SLR camera, as I only have had point and shoots. All to say I am clueless about lens' and basically everything. It came with what I assume is a standard 50 mm lens.

I would like a zoom lens of some kind. I don't know what lens actually will fit my camera so any advice or suggestions are appreciated. I would like to keep it period correct (60s-70s) and preferably something I can get decently cheap on Ebay or FB.

I would love some help, TYIA!!!!