There are lots of countries smaller and/or poorer than Sweden.
There are a number of very small countries with GDPs in the hundreds of millions of USD range. If you could buy a country for say 10× GDP you are looking at the low billions in GDP which is Bhutan or Zanzibar sized economies.
The problem is that countries are not often openly up for sale. You need military or political backing to actually get one. So you cannot literally buy a country.
On the other hand, I think it is reasonable to say that this amount of money is the value of an entire small economy, or of the entire stock market of a somewhat bigger one.