u didn't give enough info.  But the wii you will buy definitely fall in 1 of this categories:
1. Hardmodded wii - signs to look out - you can play boot legged games straight from the disc channel (i.e. the 1st top left channel)
2. softmodded wii: Signs to look out - you have "homebrew channel" installed. its just one of the channel if the channel menu.
3. Both Hardmodded and softmodded wii - as above.

to make a long story short, above are modded wiis, and they come with some hassles. 3 is the most hassle, followed by 2, then 1. Hassle free is unmodded, meaning spanking new US set. The list of hassles is complicated and long, so i won't expand it here, but you can easily google them. Hassle free is unmodded and that is what i would advise to buy, coz that is how it comes out of the factory. why do people buy modded wii's although it is not hassle free? that also u can google them. it is quite obvious it's worth the hassle for some people (some are legit - like u can pick up a game anywhere (us, aus, hk etc) and it will still be able to play; and some are not legit). just identify your preference and buy accordingly. good luck