Mistake ..

[DTYJ]

At a start I bought in 0.29 worth of Bitcoin at 785.00 USD and just accidentally sold it at 750.00 USD.. How dumb am I for making a mistake 

[Sindelar1938]

Tough, but you will live!
Good luck

[Foxpup]

How dumb am I for making a mistake

You are ten dollars dumb. Or ten dollars smarter, depending on whether you learnt anything from this event.

[gekkomk]

It's a life experience. Learn from it and keep investing.

[1FfmbHfnpaZjKFvyi1okTjJJu]

You can rebuy 0.31btc. Good trade.

[Itun]

Well, you only lost about $10.

But, this may be a priceless experience.

With the experience, you might get so much more later.

[lunatyk913]

you could've done worse.

[qosmio]

here is my mistake:
almost every time I buy it gets lower

[Itun]

There are bitcoin exchange simulators online.

Search for them (I forgot one that I just found out about) and use them to try things out for experience.