You’ll get your absolute best results printing the zine off of a color duplex printer. I personally print all of my proofs on a single-sided, black and white printer and it still looks great. Ads for conventions I like to support have been added mostly as filler to ensure that new articles will start on right-facing pages. If you’re not printing on a two-sided printer, than feel free to lose the ads.
If you choose not to print, the zine will still look great on the PDF viewer of your choice.