I am planning to build a 4' x 5' "deck" about 2 feet high by the back door. I figured I would do the whole thing out of ipe. The surface under my deck will be an old concrete patio. At McFeelys I found stainless steel post bases that I could use to secure the posts of my structure, but these post bases are $50 each. If I use a post at each corner of the structure that's $200 which makes these post bases a large fraction of the total project cost. Stainless steel seems to be recommended in general with ipe because the wood outlasts other fasteners. (I have read that with the latest pressure treated lumber you are supposed to use stainless steel in any case because the wood is very corrosive, so this would be an issue even if I used that instead of ipe.)
So the question is: are there any less expensive stainless alternatives for securing my small structure to the concrete patio?