What are treatment options for adult w/minor crowding of two front bottom teeth? i hear invisalign is very expensive. are there other cheaper options?

Express Invisalign: Consider express Invisalign. It is faster and less expensive especially for minor tooth movement. A removable appliance can also be used. Minor crowding can turn into major crowding if not corrected in a timely manor.

Probably: See your own dentist and/or an Orthodontist for a consultation. Each case is different. What seems simple is often not so and what seems a problem is often easily corrected. The only way you will know is to see someone for an evaluation. Also consider getting the best treatment and long term results rather than a quick easy and inexpensive "fix" that will not hold up over time.

Treatment cost: Not sure what you consider expensive, or what your budget might be, or the complexities of your minor malocclusion. Why not get a treatment estimate from a local orthodontist? This way you'll know what option could work for you, what they cost, and if it is in your budget. All the best...