Looks like goodrx actually has a relatively easy way to compare, if you go to https://www.goodrx.com/testosterone and use the drop-down menu.
I will say, in my experience, the cheapest option is always injected (cypionate) vs. any kind of topical form. Kind of a bummer if you're scared of needles or just prefer the gel, but it's been pretty consistently true where I've looked.
It's not just the TSA; I had an unpleasant experience some years ago flying through Frankfurt, Germany. I wasn't packing, but scanners flagged me because of my chest (no top surgery, I bind for travel but I guess it wasn't flat enough that time) and the agents asked me if I'd prefer English or German. I said English, because my German's not equal to that situation, and they assumed this meant I understood no German. So the one guy who spoke English asked me if I were a man or a woman and I explained that I'm trans. He translated to his associate as "both" to which she laughed scornfully and said "there's no such thing!" I pretended not to understand so I could just get through the indignity as quickly as possible, but it cemented my hatred for airport security theater.