I would like to buy a few altcoins, which websites are the safest to buy from with a credit card ?
Most known websites with biggest trust and longest working ones. Try coinbase/bitstamp etc. only most known and reliable.
Example:
I buy 10 coins valued 1$/u.
Will I spend 10$ to get them in my wallet ?
You will spend whatever exchange will charge you to withdraw them. Probably around $0.2-$5 depends on amount of transactions and actual costs of exchanges.