INDEX, MATCH: multiple criteria with iterative data

Hi there,
Since this is my first and hopefully not last post, I would like to introduce myselfe. I am 26, female, living in Zurich Switzerland and studying at the University of Zurich and working part time in the financial industry.
I have a sheet with different identification numbers in the top row and trade date with corresponding daily prices in the columns (sheet full). I now want to find (in sheet TOTAL) for a specific date and identification number the price. The problem is that the identification numbers have common but not totally equal trade dates.
I tried to solve this problem with a SUMIFS function and also with INDEX and two MATCH nested.
Any ideas?