I did a search and didn't see this posted, so I thought I'd share.
Toys R Us - Buy One Get One Half Price ALL movies now through 1/1/08. In-store only. Limited to stock on hand. No rainchecks.
I got Pirates of the Caribbean: At World's End 2-disc and Harry Potter: Order of the Phoenix...
DeepDiscount.com is currently have a Buy One Get One sale. Angel is $41.97 so that's about $21 a season. If the discount doesn't show up use code BOGOFOXMGM at checkout.
I saw season 1 and possibly 2 while at Walmart today for $19.96, but YMMV. DeepDiscount.com has 1 & 2 for $24.99 each. Until there's a decent sale season 3 can be found for $20-$25 each part.