There's any alternative to using a dental flipper besides leaving the tooth space opened(or a bridge)? can a pontic be bonded for aesthetics/function?

Usually yes: A resin bonded bridge can usually be fabricated as an alternative to the above mentioned treatments. It really depends on the condition of the abutment teeth, existing restorations, occlusion, etc. Discuss your options with your dentist.

Replacement options: Find a dentist whom you trust and who can go over all your treatment options, both temporary and long term to replace any missing teeth. Understand the pros and cons of each one, think it over carefully and decide on the best long term solution! stress the health of your teeth, your body and understand the difference between value and short term cost. You will be happier in the end.

Lots : Long lasting replacement is implant/crown or bridge. Shortest lasting is one of many removable appliances such as a flipper. And there are many alternatives in between. Talk to your Dentist or a specialist Prosthodontist about the choices that would work for you/cost/longevity/pros & cons. Do your homework with a Dentist you trust, then follow his/her advice.