Is it wise to invest in robo advisors even with a few thousand dollars (1-2k)?

Well I think whether a not it makes sense to invest your $1-2k with robo-advisors depends on your investment goals and investment horizon. If you're a long-term investor, I'm sure you would've heard of the saying that it is always good to start early, to reap the most benefits from compounding effect in the long term. Thus, it would make sense if you intend to leave your money with the roboadvisors in the long run (assuming that this $1-2k is your leftover money after setting aside money for your emergency fund, insurance and debt payment)

If you're intending to invest in robo-advisors to double/triple your money in the short term, then it would be the wrong approach, since robo-advisors often stress long-term gains. If you look at the short term gains (1-3years) for robo-advisors, they are pretty much negligible.

It would depend on your risk appetite as well as your investment horizon.

If you're set on investing with a robo advisor, shop around until you find one that you can trust.

One thing to note, the earlier you start off on your Investment journey, the greater the effect compound interest has on your investment sum.