My cheapie trick (plus its easy); NYX's Jumbo E/S Pencils. Specifically in the color "Milk" (a white). Pretty much the only product I like from NYX. Just make sure to put UDPP before the pencil, otherwise it will crease.
However, not sure if you'd want to spend your money (and time... and effort) to not only purchase these products but to learn to use them correctly (because honestly, they're tricky to use the first time, for anyone) are the water activated stuff from Kryolan or Mehron. Whenever I use them under e/s, they always make the colors pop like CRAZY. If you can only buy one, buy white or black, but if you are willing to spend more, they come in palettes. FYI they're cheaper than paint pots OR shadesticks, however you can only buy them online, so shipping may not even make it worth it. I'd say if you actually contemplate using them, really look up reviews and videos on applying them, because you may buy them and hate the effort it takes to use them.