Have you tried related records?

its empty though. I've tried converting base currency to the transaction currency which is in USD but it doesnt match the value in "Amount" field. I read from this link: https://www.mibar.net/blog/creating-a-save-search-in-netsuite-for-transactions-with-related-records/ that it is supposed to be the amount in base currency but again, it does not match the base currency that was recorded in the bill

Amount (Foreign Currency) seems to work best

Switch your Consolidated Exchange Rate setting (top of the Results tab) from Per-Account to None. The amount field will be your base currency amount if you have that set to None. However, what it's doing if you leave it at Per-Account is taking your base currency amount times your consolidated exchange rate for whatever time period you're running the search for. So if you're looking at a transaction on a EUR base sub, that Amount field will show the base EUR amount if you have that setting to None. If you have it set to Per-Account, it will take your EUR amount x Consolidated Exchange Rate of whatever the parent sub is of the EUR sub. Long story short, I would in nearly all cases set that to None. The only reason not to that I've seen is if you want to tie something to the consolidated financial statements.