Scott, when I am mailing 8x10 photos, I fold a self addressed stamped large envelope in half and put it inside the other large envelope along with the photo and my letter. Usually I put $1.10 postage on my outgoing envelope and .90 on the return envelope.

Sent letter, SI mag cover, and large SASE on 9/7/12 to:
David Baas
New York Giants
New Meadowlands Stadium
102 Rt 120
East Rutherford NJ 07073

Received SI cover back signed on 12/4/12
Sorry my scanner is down

Sent letter, color 8x10 and large SASE on 5/31/12 to:
Roy Hibbert
Indiana Pacers
125 S Pennsylvania St
Indianapolis IN 46204

Received my photo back signed on 12/4/12
Sorry my scanner is down

Sent letter and large SASE on 11/10/12 to:
Jim Bunning
4 Fairway Dr
Southgate KY 41071

Received a signed HOF plaque postcard on 12/4/12
Sorry my scanner is down

Sent letter and large SASE on 11/3/12 to:
Larry Storch
336 West End Ave
New York NY 10023

Received signed/personalized 8x10 b/w photo on 12/4/12
Sorry my scanner is down

Sent letter and large SASE on 10/9/12 to:
Keegan Bradley
PGA Tour
112 PGA Tour Blvd
Ponte Vedra Beach FL 32082

Received an 8.5x11 color signed photo on 11/27/12
sorry my scanner is down

Sent letter, SI magazine cover, and large SASE on 9/3/11 to:
Vince Wilfork
New England Patriots
1 Patriot Pl
Foxboro MA 02035-1388

Received SI cover back signed on 11/27/12 (14 months but I'm pleased)
sorry my scanner is down

Sent letter, photo, and large SASE on 11/17/12 to:
John Paciorek
7118 Hidden Pine Dr
San Gabriel CA 91775-1216

Received photo back signed on 11/27/12 along with a hand written letter.
sorry my scanner is down

sent letter and large SASE on 11/10/12 to:
Jimmy Carson
1154 Ridgeway Dr
Rochester MI 48307

received a signed/personalized 6x8 color photo and signed hockey card on 11/23/12
sorry my scanner is down.

sent letter and large SASE on 10/9/12 to:
Jamie Nieto
USA Track & Field
132 E Washington St Ste 800
indianapolis IN 46204

Received 3 signed 4x6 color photos-one personalized on 11/23/12
sorry my scanner is down