How do I do this exact same thing, but wtih an arbitrary number of nodes

I have the following code in an xslt.

<xsl:sort
    select="concat( 
        (com:prices/com:price[1]), 
        (com:prices/com:price[2]), 
        (com:prices/com:price[3]), 
        (com:prices/com:price[4]))" />

The problem is that its hard coded for only 4 prices, when there could be an indefinite amount of prices. Whats the syntax for concatenating all available price nodes?

Apologies for the noob question, but xslt is one of my worst/least experienced languages and all of the examples I've found online seem overly complicated.