Yes, you could buy 15 of those for the cost of one
Night Vision Pen. However, it would most likely take more than 15 to last as long as a single Night Vision Pen. Who do you contact if it doesn't work two weeks later? The Fisher Space Pen ink cartridge in the Night Vision Pen alone retails for $5.00 because it will work in any pressure environment, write upside down, and in temperatures from -30 to 250 degrees - that is just one indicator of the quality that goes into producing a Night Vision Pen. That $6.95 pen is more awkward to activate the light than the ergonomically located activation button on the Night Vision Pen. It has no lanyard loop and it breaks easily - trust me, I have tried them in the past myself.
Here is a mission that is very probable in your near future: You are finally fully mission qualified in the Prowler (the aircraft indicated in your profile). It is a daytime launch in the Persian Gulf for a late night recovery. Flight deck temperature is hovering around 120 degrees. You finally strap into the jet after the preflight and start to take notes for the launch and your $6.95 FL-PEN is leaking all over your mission card from the heat. You have about an hour and a half transit up the Boulevard to get to your killbox, the sun setting while in transit. Your VUL window is four hours and everyone dons their goggles. Things are pretty chill in country at first when you check in and you are kind of getting jerked around from controller to controller. You just activate the light on your pen and leave it there because it is a pain to keep turning it off an on. A Task Force mission (if you don't know what it is, just know it is extremely high priority) comes up and they need your capabilities to support their mission immediately. Things are happening fast now. Their mission runs longer than expected so your VUL is extended to support them. The SODO at the COAC arranges for a tanker to meet you by your killbox for additional refueling. They also relay to the carrier that you will be late and you were already on the last recovery. After a six and a half hour VUL the Task Force mission is finally concluded and you are released to start your long transit back to the boat. When you check in for marshal instructions you go to turn your FL-PEN on, but it isn't working. You realize that you never actually turned it off and the batteries ran out because you had left it on the previous couple of flights for hours as well and the batteries only have about an 8-10 hour constant run time. You break out the Grimes light and ask them to repeat the marshal instructions while the boat turns into the wind. Your department head pilot is getting pissed because he has been airborne for nine hours, he didn't bring any food, your asking marshal to repeat instructions and you are, at least to him, shining the Grimes light into the side of his face. The entire flight deck crew is running only to catch your jet hours after they were supposed to be done. You finally trap and have one of the ECMOs in back hand you their fingerlight to signal your "up" status, but it gets dropped during the exchange. Your fight deck coordinator is trying to get your attention and eventually you have to call over the radio that your jet is down for FOD in the cockpit. At maintenance control, your A-hole department head pilot loses his cool and slams his fist on your helmet bag that is on the counter, snapping the FL-PEN's flimsy and hollow plastic body. You didn't buy 15 because one was good enough, right?
Some people choose to work with whatever is provided or cheapest. Others choose to invest in a quality product that will last. Buy a Night Vision Pen for yourself and see the difference. There is a 30 day money back guarantee if you don't like it. Let me know you want to return it and I will refund not only the cost of the pen, but also the cost of the original shipping
AND the cost of return shipping. You have nothing to lose.
