I don;t use external speakers on any of my systems...headphone for all...so let's see what we can find on Newegg:
Price range? Here's a link to Newegg using the Highest Rating choice: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007679%20600010685&IsNodeId=1&bop=And&Order=RATING&PageSize=50
You can see the best is $80 and the next best is $300+. This assumes 5.1 sound.
As for wireless I use USB wilress dongles for almost everything. Do they have G or N? They are simple to use (plug into any open USB slot), easy to set up, don't need a card slot. Lots of brands and prices can range from the mid $20's to $50 unless you buy refurb.