Using a window air conditioner

I wonder if it will be worthwhile to purchase a portable A/C unit. I currently live in the north, where it gets hot for only two months total out of the year. Usually, those two months are extremely hot, although the  humidity is the absolute kicker. The portable air conditioner would be great to have for work and also when I am sleeping. I work online, almost entirely out of my home. The two months of summer are difficult to get through without a cooling system. My laptop naturally gives off heat, causing me to sweat profusely when I am working, sometimes for several weeks at a time. It would be pleasant to feel the air conditioning blowing on me while it is providing climate control. The A/C would be helpful at night when I can’t sleep because I am sweating to death. Neither opening my bedroom window, nor using window fans provides any relief. The fans just circulate the hot, stuffy air around my room. Without a doubt, an air conditioning unit would get used, but I worry that it  would only be used for the two months of the summer; after that, it would sit unused for most of the rest of the year. Depending on the air conditioner that I select, I expect to invest about $300.00 in it. I wouldn’t want to put that much money into purchasing an air conditioner it if it is not worth my investment. I plan to move down south in a few months, and I am sure I will make more use of an A/C unit when I’m living in the southern climate. I’m concerned whether it will it be worth the cost of moving a $300 air conditioner that will sit unused most of the time, or whether it would be better to just to buy a new and probably better air conditioner when I get there. The place I eventually rent down south will most likely already be equipped with central air conditioning.