Thank you for interest in AndroZip. Yes, it is beta and right now it is free until 30th of May 2009. Even if we did test this application it might happen that there are bugs. Right now we are working on web site with help section and will create place for customers to report issues.
Our plan is to support other popular archive formats. Also before releases we want to make detailed tests so even if we have working version of program that unpacks RAR format we didn't want to release AndroZip with unrar functioanality because it is not tested thoroughly.
When it comes to price right now it is free and sometime in future when it becomes commercial it will be very cheap. I belive that its price will be in 1-2 dollars range.