The S80 is a heavy beast. It weighs in at about 24 Kg, or 53 lb for those using archaic measuring systems, and that does not include cables, stand, bench, headphones or amplifiers or speakers, or any of the other things you actually need to play the thing.
This appendix assumes that you have already gone through the initial pain of carrying the S80 in its cardboard box, which makes the whole package so unwieldy as to make you want to throw it out the window, if you were only able to actually get the damn thing up there. But you should resist the temptation — the S80 is sturdy, but it is not likely to survive a fall from a building.
Unless you have a couple of carriers to haul around the S80 in its box, which will protect it nicely, you'll want to throw the box away and carry the S80 in some other fashion.  If you are brave and poor you can carry it around with no protection. Pass one of your forearms under the keyboard, use your other hand to grab it from behind, and use your third hand to open doors while you take it to places. The first time you do this you will break a dripping sweat, curse the S80 and its mother and its grandmother, and you will wonder if you should be playing the piccolo instead. After a few weeks of carrying it around regularly, your arms will grow strong, your third hand will be very skilled in fumbling with keys to open doors, and you'll think that people who are out of shape don't need to go to gyms and they just need to get a synthesizer with weighted piano action.
Some time after you purchase your S80 you will have money again, so you can buy food and a soft case for it with a large, comfortable carrying handle and a sturdy strap. You will have to learn different skills this time so that your shoulders will do most of the carrying rather than your arms, and you can dispense with your third hand because now your arms are free to battle doors and other obstacles.
A soft carrying case, however, will not help you out when you have to take your S80 on an airplane. Baggage handling will completely kill your instrument unless you have a hard carrying case. This is even bulkier and heavier and dreadful than the original cardboard box where your S80 came in, but it is absolutely necessary for air travel. Get a hard case with a heavily padded interior, and hire two strong men to carry the whole behemoth for you. If you can't get them, politely ask your other band members to help you out. Your drummer is already used to carrying around his mess and is likely to be the strongest member of the band — make him do something useful.
Here are some tips for when you have to carry your S80:
If you have a keyboard stand that folds into a flat contraption, you may be tempted to put it on top of your bare S80 and carry both of them at the same time. Do not do this. The S80 has a slippery surface and the keyboard stand will slip, taking out one of the S80's knobs with it. It did not quite happen to me like that, but it managed to damage a knob so that it no longer snaps in its center position.
When stashing the S80 in the trunk of your car along with your backpack and other items, be careful when you take the smaller items out. Backpack straps love to get caught in the S80's knobs and key rims, and you could inadvertently tug them out if you are not careful.
 Better still, don't throw the box away. Keep it in your fantastically tidy and organized junk room or attic. You will find it useful some day.