Desparate SUMIF and VLOOKUP combination?

Hi,

I have uesd this great forum several times to find answers to general questions but this time I could not figure out how to solve my problem by checking others post. So here is mine.

I have two sets of data. Orders and current stock. I want to match orders with the stock and see how much I have in stock for every article number and return the stock amount. The problem is that the same article number might appear several times in the stock and therefore I need to SUM the total amount in stock which matches with the article numbers.

Also. I want to write the markup price where I compare cost of good to price to customer with a simple price/cost (but need to match with right article number).

Please help me out as I need to deliver these results rather quick.

BTW: I would also want to ask how to use the Vlookup formula or similar to match information that is ALMOST the same and the same. Example if ABC1234567 and 1/ABC1234567 are in two different columns I would still like the formula to identify them as equal. Is it possible?