problem with lens on Canon T3i - total newbie needs advice

I probably should have asked around for advice first. I have always wanted to get a really nice camera and recently had some financial good fortune so I decided to treat myself to an upgrade from Samsung S730 and bought a second-hand Canon Rebel EOS T3i 600D. The person selling it said it was like new, not that I would know the difference lol.

I never before had this type of camera and know nothing whatsoever ever about the kind of cameras that have removable lenses and stuff. This would be my first. Up until yesterday, the Samsung was the fanciest camera I ever had and it was given to me by a friend when they upgraded to a nicer new camera.

Going by the seller's description I thought there would be three lenses with the Canon and they said it was like new so I bid pretty much all of the money that I had to put to a camera and I am never that impulsive with spending, as I am on a very low fixed income. When the camera arrived in the mail it had it's original box and battery, wiring, manuals, etc and looked almost new cosmetically, though there was just two lenses and one was already on the camera inside of the box. When I went to test out the camera, it had a huge handprint smudge covering most of the lens after I removed the lens cap. I know lenses are supposed to be delicate so I was wary about how to clean it. I tried a little cleaning cloth that I had (made for eyeglasses) and of course that didn't remove the smudge. I don't have any lens cleaner and didn't think to buy any online before the camera arrived (I'm disable and don't drive so I shop online). I used a drop of Windex before I read someone online say you should not use Windex on a lens. It didn't remove the smudge anyway. I used tissue paper with the Windex. Regardless the lens just seems to have a film that won't remove, as if maybe it is on the other side of the lens. Did the Windex ruin the lens or could the hand print that was already on there when I received it spoil the lens by having oils from human hands on the lens for some period of time?

The smudge lens is the one labeled 18-55 mm and says macro on it as well, which I think was original to the camera. The second lens is 55-250 mm. That one did not have a smudge and seems okay but I really couldn't take a photo with it. I was trying to take photos on macro mode and it wouldn't focus. It wouldn't focus for regular photos either (I was on auto focus mode and also the one with the + sign to take auto setting photos).

The test photos I took were taken indoors at night. It ran out of battery  so I couldn't test it too long. I have a lot to do today so I can't play with it today to test it further and I don't want to take it outside yet as I don't have a tripod for it and don't want to risk dropping it. I was having trouble figuring how to change settings and such but I know about macro mode since I used that on my other camera. I used the instruction manual to change the lenses and went back to testing out the original lens, took a photo in macro mode on 18mp setting. I couldn't figure how to get the camera to take a photo by itself, like with the Samsung, because the menus and all the buttons and stuff were more complex than my Samsung camera and it was taking me forever by having to consult the manual for everything. That setting is useful so there is no vibration affecting the focus (I think it is self-time mode). Even so the focus on the test photos seemed pretty sharp except for an obvious area to the right of the center, which is of course due to the smudging so it affects the photos and would make the lens un-usable if it can't be removed. I could upload the test photo if this website allow that but of course it is huge photo that is like 1.28 mb

I'm wondering if I made a bad choice to spend so much since I didn't know if the camera was really worth that much and possibly it has damaged lenses. I know it is an older model but since the seller said it was like new and included all original accessories I felt like it could be worth that much and spent nearly $400 on it. Now there is really no money left to be buying another lens or anything. As it is, I found I will have to buy lens cleaner and a air blower gadget and other things people said are needed with this type of camera (little pen brush). I don't want to ruin the camera, as I could never afford another one It came with a camera bag so I put everything back in the bag for the moment. It seems to have all the accessories that should be there; manuals and CD-Rom, battery, charger, cables, lens covers, etc.