Is the model wifi and 3G. If so you can get a Samba sim, which lets you view ads for free data. You don't have to actually watch the ads but you do get 3.5mb for each one viewed. You can build up your mbs before you go away. I do this and keep topping up as I need to. You can also pay for the mbs but they only last for 30 days, same as other sims. However, the ad mbs don't have a use by date.
This is a great way to free access if you don't mind the ads.