Ok, I'm no doctor or anything so you get no guarantees at all, but this is all free info just compiled here in one nice thread. This will attempt to explore all the approaches of dealing with this problem without requiring surgery or treatment pills.
1. Excessive skin has been treated with some success on woman's faces for a long time with cucumbers. The idea is you take the cucumber, cut it open or into slices, and rub the juices on the skin you wish to tighten. Then let it dry and wash off. Repeat daily I suppose. I have no cucumber farm so don't be mailing me money and expecting some cucumbers. :-P Just drop by your local farmer's market and make sure the cucumbers you get haven't been treated with pesticides(aka organic).
2. Push-Ups: I recommend starting with 30 of these a day. If you need to stop between go right ahead. However, this can probably really help out a lot as it will tone the muscle underneath which will result in pulling the skin tighter over the muscle. This will also help burn fat on your chest. Avoid high weight bench pressing during this time as that will not tone the muscle but will only build more muscle and not eliminate the fat. You need the muscle toned! (In my opinion at least.
) Try to work up to 50 a day. Then see if you can make 70 a day. Then try for 100/day(to do this, find 3 times a day where you do 33 push ups)!!! The idea is you are toning your chest and by doing so, your body will shape it over time to the most efficient shape for doing that many push ups! That shape is pretty good looking I might add. At least the ladies think so! ;-) Running several miles can help too as it keeps your arms in motion for a long period of time. Combine both for best results!
3. For your diet, resort to drinking LOTS of green tea through your day. Sweeten it with Stevia as that has no calories(find non-bitter aftertaste version at health store). Don't buy the bottled green tea crap. That stuff is way sugared down. Buy loose leaf green tea at an asian store and boil some water(64 oz.) to pour over about 3 tablespoons of it and let it sit for several minutes(5mins) before draining out the leaves. Keep that green tea in a insulated container and pour over ice throughout the day. Make sure you drink it ALL!!! Also, get some chromium supplements at your nearest supplements store. Also, eat a higher protein diet, lots of meats, and also lots of vegetables. All these things will help raise your metabolism. Make sure you NEVER GET HUNGRY!!! That tells your body to store fat. Instead, eat small portions of food throughout the day. Maybe make yourself some shaved turkey/lettuce/mustard rolls and carry these in a cooler or store in your work place refrigerator.
4. Patience. You didn't get man boobs over night and they aren't leaving over night either. You have to work at it. Come to grips with that up front. Take pictures before you start and put them in a drawer hidden somewhere. Then take pictures after a month. Put those there too. After 2 months, 3 months, etc. Before you know it you'll be seeing an amazing difference.
5. If you wish to pay me for this awesome advice, please reread sentence 1. You probably couldn't pay me enough anyways.
Keep your money and spend it on something useful like your most favorite libertarian candidate running for office. Alright, peace out all.