Yes it is certainly possible to buy just the Forms ES2. LiveCycle is modular and each module is available separately or in bundles.

Regarding pricing, I’d recommend you find a Solution Partner to work with who and can quote you the appropriate licenses. The partner finder on Adobe.com is here;
https://www.adobe.com/cfusion/partnerportal/index.cfm?event=partnerfinder&showtab=solution&loc=en_us

I think you may be referring to the LiveCycle Data Services ES2 component which is just one of 15 available LiveCycle modules. If this is the case its probably worth pointing out that while you are correct that the LiveCycle Data Services ES2 Enterprise Edition has a list price of $30,000 (and who pays list price these days?) this price includes 5 copies of Flex Builder Pro and the productivity & business benefits far outway the cost. I’m not sure what you pay (or charge) for development services, but the cost saving in development time alone by using LiveCycle Data Services often justifies the licence costs. Data Services customers also see a reduction in cpu requirements and network bandwidth.

For smaller projects Adobe also has made a cut down feature set available for free as the open source Blaze DS. Finally if you have a collaboration project in mind, check out LiveCycle Collaboration Services, a hosted service that allows you to get started without deploying any infrastructure, and you only pay if your load goes over a certain threshold.

If you are referring to LiveCycle ES in general, then you can get a whole lot of value for far less that $30k, and many many customers have been able to meet their business requirements with small cost effective deployments

Mark