i understand and do the same. i have knives tucked everywhere, and none of the back-ups are the fancy one. i reserve the "best" for what i carry on me 24/7.
because i rarely trust low-cost folders to lock-up perfectly, i just as soon use slip-joint folders, which forces me to use them only for cutting/slicing, not "prying" (by which i mean, any sideways or reverse pressure at all).
with that in mind, one of my favorite "survival kit" knives is the flat/thin/sharp/inexpensive/high-quality/extremely-rust-resistant Victorinox SAK Solo Alox
http://www.sakwiki.com/tiki-index.php?page=Solo+Aloxseem to be available thru amazon for $16
http://www.amazon.com/Victorinox-Swiss-Pocket-Silver-Ribbed/dp/B0007QCO7E/ref=pd_sim_sg7.