Am I financially responsible for bed bug testing/extermination?

Bedbugs are almost always the tenant's responsibility to pay for because the travel on-person, on someone's clothes, in luggage, etc. They don't crawl under the doors like typical bugs from outside might do. Bedbugs are pretty small as well, you can see them... but you describe larger bugs in your area. Yes, it's likely to cost much more than $100... bed bugs are very expensive. You need to pay for the proper identification before you make any decisions. You may choose to get rid of your current mattress, but it won't do you much good if you don't take care of the problem through extermination. Going to Asian countries doesn't mean bedbugs... the US has an extremely high rate of bedbugs right now and the majority of hotels have had reports of bedbugs. You could have easily brought them in or a friend could have brought them in... with neither of you ever knowing.