Last time i took the plane to London, they were distributing sim cards from operator T-Mobile for free in the plane, and I asked the stewardess to give me some more. i ended up with a few of them and was able to create several mobile certified accounts on Facebook, Gmail etc.

So first, I'm sharing this idea and then I'm asking if somebody knows some other ways to get cheap mobile phone sim cards with a phone number. I think it's quite a good ingredient to have in any black hat social media strategy.

U may find in ebay or in Fiverr

That looks like an easy way to get a Sim. Things are different here in India as it involves very strict procedure to get one. Nonetheless try fiverr and check, you never know what is in store there .

yeah buy them from ebay less than $1 each.

It really depends on where you live. On some countries, you can get as many as you want.

If the sim card is only needed to verify different accounts for SEO pupose then it is good to ask for a separate email account for SEO from the client side only. He/she can create website email for your work.

Thanks for your tips, I will have a look at ebay. I believe certified accounts have more weight in social networks algorithms, and makes the overall more "realistic".