Like everything else, you have to decide what expenses in your life are "must have" and which are "optional". To me, the hassle of trailering my boat and dealing with the launch/retrieve hassle makes the cost of a slip or valet service worthwhile.
If you're eating ramen noodles already and still want to enjoy your boat, then you need to cut some expenses somewhere, and trailering might be what does it for you. Personally, I'd eat ramen before I'd deal with a boat ramp