Have come to the profound conclusion - that the only valid reason to build your own table is ---
I want to.
pleasure of the work -- pride of workmanship -- have something there isn't another like -- etc.
I say this as I near the end of builidng my own.
You clearly won't save time - and especially if you count your time of value -- you won't save money either.
Saving money was one of the ideas in the back of my head --but by the time I kept adding ideas --- ----- --- I've invested about $50 in materials -- just to find Rockler putting a table on clearance that would have been almost perfect for my needs -- for --- you guessed it --- $50.
I'm not sorry about my decision -- I did enjoy the building - and I do like having something unique.
BUT -- if I had it to do over -- knowing what I know now ---
---- I think I would have bought at LEAST the top and fence.
And Rockler is - in my experience - a very good source.
I think you are making a wise choice.