I had 60 days tourist visa and I extented with a month more already so the total is 90 days.Can I go to the iimigration office and ask for 7 or 10 days more?

Sure you can go ask!

You won't get any more days unless you have a ticket out in 7 days or less from the date of expiry, but you can always ask!

Sure you can go ask!

Are you sure you can just ask?

I thought you needed to fill out an application form (TM7) and present it with the fee of 1,900 baht for consideration. If they don't give it to you, you've blown the money as it's only a application fee.

Immigration has been very good at not doing that - in fact I have had them refund the 1,900 baht fee when I applied for an annual extension but had to obtain more paperwork. In all cases I have seen they try to make sure you qualify before they even take your money.

But for the OP - not more than 7 days will be allowed and for that you will have to supply an outbound ticket showing your departure date.