Every two months in Bali you need to do a "visa run" — leave the country and come back to reset your visa. Most people do Thailand or Singapore. I chose Singapore, and I'm glad I did.
1. Fly AirAsia. The Denpasar–Singapore route on AirAsia is almost always under $80 round trip if you book a few weeks ahead. Bring only a carry-on and you'll pay even less.
2. Stay in Little India. Singapore is one of Asia's most expensive cities, but Little India has guesthouses for $30-50/night that are clean, safe, and perfectly located. The food in the neighborhood is extraordinary and costs almost nothing.
3. The hawker centers are the move. Singapore's famous food courts serve world-class food for $3-6 a dish. Lau Pa Sat, Maxwell Food Centre, and Chinatown Complex are my favorites. Do not eat at restaurants near Marina Bay.
4. The MRT will take you anywhere. Singapore's subway is one of the best in the world and costs pennies. Don't take taxis.
5. Gardens by the Bay is free (mostly). The Supertrees, the outdoor gardens, the nightly light show — all free. Only the indoor cloud forest domes cost money.
6. Stock up on things you can't get in Bali. Decent cheese, good wine, Western medicines, specific supplements, quality sunscreen. Singapore has it all at prices that feel expensive compared to Bali but are actually reasonable compared to the US.