How many cost an altered card?

Normally the artists calculated the price of altered depending on the design card. The more complicated it is, the longer need to paint and more expensive will work.
Apart from this, each Alterer has its own rate, which can vary depending on the quality of the painter. The average is usually 10 € / hour.

How long does my card would be completed?

For most of the Alterer, this work is a hobby and have their own work out. Depending on the amount of Alterations, each artist has his own range of time. It is good to ask this when a commission is asked to avoid problems once the cards have been sent.

What type of pigment used to paint altered cards?

99.9% of the artist uses acrylic paint (citadel, vallejo, etc)


Can I play my card in altered mtg tournament?

What wizards say:

3.3 Authorized Cards

[...]
Players may use otherwise-legal non-English and/or misprinted cards provided they are not using them to create an advantage by using misleading text or pictures. Official promotional textless spells are allowed in DCI-sanctioned Magic tournaments in which they would otherwise be legal. Artistic modifications are acceptable, provided that the modifications do not make the card unrecognizable or contain substantial strategic advice.

The Head Judge is the final authority on acceptable cards for a tournament.