If I have any money left over, I will buy some more souvenirs at the airport.
If I have any extra cash at the airport, I'll buy a few more gifts for friends and family.
ーIf I have any money left over, I will buy some more souvenirs at the airport.
「もしお金が余っていたら、空港でもうちょっとお土産を買います」
If I have any money left over で「もしお金が残っていたら・余っていたら」
souvenirs で「土産」
ーIf I have any extra cash at the airport, I'll buy a few more gifts for friends and family.
「空港で現金が余っていたら、友達と家族にもう少しお土産を買います」
If I have any extra cash で「もし現金余っていたら」
ご参考まで!