Tuzz, you might consider a floating structure. I built a 10x10 floating dock using plastic 55 gal barrels that you can get at a farmstore or at a soft drink bottler as throw aways. The cost was about 500$ mostly for the treated lumber deck. the barrels go for about 6$ each and I happen to already have them on hand.
Or you can wait for a draught, mine took 8 years to occur, I recently finished a 16x16 peir to replace it. The structure I used was railroad ties for post and beam structure and then built 2x6 treated deck on top of the railroad tie structure.
