This is going to sound totally ridiculous, but I'm asking on behalf of a friend who's got a project planned for his degree in tourism at university.

He wants to obtain as many visas as possible, for exotic/rare countries, e.g. Turkmenistan, Bolivia, Gabon - all the places that 99.99% people have never been to or heard of.

He'll then write a thesis based on how easy it was to obtain each one, what requirements were needed etc.

The trouble is that some countries charge extortionate fees - e.g. Pakistan is GBP 104 for a single entry tourist visa!! The other problem is that many countries need invitation letters, or proof of flight/accommodation booking.

So my question is: Which countries offer tourist visas, for a reasonable cost, and without needed proof of actually visiting, or masses of paperwork and letters?

Thanks for any (useful!) help, and sorry if this question sounds ridiculous.