I think you can create 2 custom post types, Product and Supplier, and then create a number field for the price and post object field for the suppliers. You can set these two fields for the Product.
To get the highest and lowest prices, you can order the posts based on the custom field. This page should give you more idea about it: http://www.advancedcustomfields.com/resources/orde-posts-by-custom-fields/.
If you want to calculate a complex thing using these data, I think a custom table would be more appropriate.
Please try the free version first here: http://wordpress.org/plugins/advanced-custom-fields/.
I hope this helps.
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