How can i search my dad for free?

[Bo Peep]

It depends on how much information you have already.

You need to create a file and record everything that you do know.

His name - full name - middle name if you know it.
His date of birth - or even the year of birth will help
Where he was born
Where he lived/grew up
Where his last known address was
Brothers, sister's names
Parents names
Place of work
School/college/university
Interests

When you have compiled all this start by a simple google check with his name and the area he lived...

Move on to checking things like Friends Reunited...see if he is listed under his old school or college.

Run his name in a 'facebook' search

In the UK you can search for him on 192.com

You can also search for him on ancestry.com

If this fails, you can start searching using his brothers or sisters names....even his parents names....

Hope it goes well for you.