Bids for Brooklyn’s Starrett City apartment complex, the largest affordable housing development in the country, may be significantly lower than expected in the wake of the Wall Street turmoil. Experts say the bids likely won’t exceed $700 million, down from the high of $1 billion predicted before last week. The National Housing Partnership Foundation, one of the organizations planning to make a bid, had expected Goldman Sachs and Lehman Brothers to underwrite its proposal, and Fannie Mae and Freddie Mac to finance it and provide credit enhancement insurance. But a cautious financial atmosphere means bidders might be able to borrow only 70 or 75 percent of the amounts they had hoped for. Bids are due Thursday.