And of course for a list of such elements you could extract a list of the items:
In[1]:= el =
XMLElement[
"price", {"id" -> "12", "selid" -> "865986582",
"marketid" -> "258568238", "auxids" -> "", "price" -> "11/8",
"pricedec" -> "2.38", "cid" -> "7x12", "movement" -> "O",
"bslink" -> "Y", "date_stamp" -> "2015-04-25 11:50:21",
"opprice" -> "", "oppriced" -> ""}, {}];
In[2]:= el2 =
XMLElement[
"price", {"id" -> "13", "selid" -> "865986582",
"marketid" -> "258568238", "auxids" -> "", "price" -> "12/8",
"pricedec" -> "2.38", "cid" -> "7x12", "movement" -> "O",
"bslink" -> "Y", "date_stamp" -> "2015-04-25 11:50:21",
"opprice" -> "", "oppriced" -> ""}, {}];
In[3]:= {"id", "price"} /. {el, el2}[[All, 2]]
Out[3]= {{"12", "11/8"}, {"13", "12/8"}}
You could also quite easily build a list of Associations so that you could extract data by Keys.
In[4]:= data = Association /@ {el, el2}[[All, 2]]
Out[4]= {<|"id" -> "12", "selid" -> "865986582",
"marketid" -> "258568238", "auxids" -> "", "price" -> "11/8",
"pricedec" -> "2.38", "cid" -> "7x12", "movement" -> "O",
"bslink" -> "Y", "date_stamp" -> "2015-04-25 11:50:21",
"opprice" -> "", "oppriced" -> ""|>, <|"id" -> "13",
"selid" -> "865986582", "marketid" -> "258568238", "auxids" -> "",
"price" -> "12/8", "pricedec" -> "2.38", "cid" -> "7x12",
"movement" -> "O", "bslink" -> "Y",
"date_stamp" -> "2015-04-25 11:50:21", "opprice" -> "",
"oppriced" -> ""|>}
In[5]:= data[[All, {"id", "price"}]]
Out[5]= {<|"id" -> "12", "price" -> "11/8"|>, <|"id" -> "13",
"price" -> "12/8"|>}
In[6]:= Query[Select[#price == "11/8" &]]@data
Out[6]= {<|"id" -> "12", "selid" -> "865986582",
"marketid" -> "258568238", "auxids" -> "", "price" -> "11/8",
"pricedec" -> "2.38", "cid" -> "7x12", "movement" -> "O",
"bslink" -> "Y", "date_stamp" -> "2015-04-25 11:50:21",
"opprice" -> "", "oppriced" -> ""|>}
Although the syntax of the new Dataset capabilities can be a bit obscure.