A good comfy saddle is not something you should skip on. You will be riding around on your tushy for hours - so it is very important that you are comfortable. During these long hours your pants especially in the crotch and the butt will get a lot of wear and tear due to the friction and leg-pumping-action (LPA). Check for small holes often - before you know it they get bigger and bigger...
If you catch it in time, a tube patch kit might save your pants from turmoil.