Buying a sub $300 bike for use in Aruba seems.....well adventurous
.
If it is just for the paved roads, it might hold for a while, but I you go off-road you probably have to triple that amount
(if it is a new one).
Normally it is no problem at all to bring a bike on the plane, but the will probably charge you around $100 to bring it.
P.S. Remember that a stick is part of the standard equipment for biking in Aruba.
Carsten