I was wondering, when you don't use capo playing songs that uses a capo, it would still sounds "ok" right? it will be just in another key?

I just played wonderwall without a capo and it didnt sound that bad
yup, it'll just be in a different key.
although in many cases, depending on your range and the range of whoever usually sings it, it'll probably be harder to sing because of the different key..
Yep. Most songs that are tuned down half step I also just play in standard. If you're playing with other instruments this could be an issue, but for just playing on your own you can play without changing tuning down 1/2 step or adding capos, just adjust the singing accordingly and rock on
My Gear
Epi Les Paul
Roland Microcube
Boss DS-1 pedal
Shure SM57
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If you mean moving the capoed piece to the nut (as the capo is there) then you'll be playing in a different key. If you were playing the same position but the capo's removed then you might have some open strings in your key.

1) Play it in a different key.
2) Use a finger to barre where the capo would be
3) Transpose the chords. I.E. If it's capoed on the 2nd fret and the chord progression is written as G, C, D relative to the capo, than you just take those chords and write them a whole step higher, making the actual chord progression in that example A, D, E.