Bitcoin has been advertised as a very low cost and fast method of sending people money around the world, So if I need to send someone $1000 USD, the cost/fee of using WU is less than $20 USD (Using credit card - UNFORTUNATELY, WU doesn't work. They deny me sending $1000 and give me no reason. I will never use WU again.) but if I use bitcoin, what will be the minimal cost? Since I need to buy the bitcoin in the first place, and that other person need to sell it to get the cash, the conversation fees and the transaction fee would be more than $100 in the end? and if send someone $1000 in bitcoin, there is a chance that when she/he gets the cash next day, my $1000 will be less than $1000? If that is true, how can I trust bitcoin?
If you pay enough fee, which is ~ 5 dollars currently (but paying 10 dollars will guarantee fast confirmation), your payment will get confirmed in an hour. Good luck!
Actually it's possible to send with lower fee by using a SegWit address, but don't take the risk if you don't know what you're doing, set its fee 8-10 dollars. Rescuing the low fee transaction is difficult unless you're an expert.
have a look here: https://bitcoinfees.21.co/ this tells me currently, that you can pay 120-150Satoshi/Byte, to get confirmation within 6 blocks (on average 1 hour). So if you have a standard tx (less than 500 Bytes), you can go with 500x100 Satoshi= 50.000 Satoshi = 0.0005 Bitcoin = +2 Dollars. If your tx has 2 inputs, and two outputs, then you have like 750 Bytes, so make it +3 Dollars.