I checked out some of SP late last fall. I got sick and didn't fish w/my boat or charter and a major cold front also blew thru.
I didn't check out any private offshore charters.
But I talked to a few party boat co. and they only go out 15 mi. or so to get to big game fish/deep water and use less gas so I guess thats why prices were lower than P.Aran or Galv. These prices from fall '05
I talked w/nice personel at Capt Murphy's a family run bussiness.
www.captmurphys.com 7-5pm $65, rider $35
Also had 3-4hr bay trips per day
www.ospreyfishingtrips.com 7:30-3:30 $65. 12hr blackfin tuna trip 6:30-6:30 $100
On the Port Isabelle side there was a large and a small bait/tackle store w/ back water guides.
South Padre web=
www.sopadre.com Ate at a seafood dive I think called Dirty Dans which had the best fried & stuffed shrimp and fish. It's south at the end of the road by the Isla Blanca County Park entrance.
Wish I had more info.
Grant