I think that is exactly what FF and I usually say...spend the money where it is needed most and for those of us that are on a budget..shop wisely and save where appropriate.
Being able to do that and give that advice with a clear conscience comes from a lifetime (50 plus years) of boating, repairing, professional mariner time, trained technician time, working in the industry, living aboard 3 different boats, debriefing thousands of surivors/clients involved with boating incidents, etc...etc...I don't take this stuff as lightly as some may think.
I would never advise someone to go to the big box store and jury rig a proper seacock...but I'll be glad to explain how to assemble a fresh water system that is NOT gonna sink your boat or catch it on fire with pieces and parts that are a fraction of what a marine store or design would cost/call for.