Some people report that they do feel it when they use injectables, most don't. The proteases in plasma break down the peptide before it has a chance to cross the BBB, and even then, sweet fuck all crosses the BBB. Intranasal is direct to brain.
Yeah any nasal spray will do. It depends on how often you use them. If you have one that is anything more than saline, you'll dry out your nose and possibly cause trivial damage/irritation. Benzyl Alcohol is often used in nasal sprays which is a preservative/bacteriostatic agent.
That being said, you are sticking it up your nose which is rife with bacteria and mucosa. Best thing to do is alcohol wipe the nozzle after each use and refrigerate.