Certifications are good if you have the experience to back them up. 

Lots of the SAP gigs want someone with Full Lifecycle SAP implementations ... from concept to post-implementation support / change management. Goto the SAP website and look at training opitions and info on certification. Look at Job Boards to see what skills / requirements companies are looking for.

Each vendor most likely has their own certification ... I don't know if there is a cross-the-board certification for CRM / ERP.

SAP Certification:

"The SAP Certified Associate designation is for individuals who work with SAP technologies and applications at an entry level and focuses on specific SAP applications tracks, such as SAP HANA, Business Intelligence with SAP NetWeaver, and Financial Accounting with SAP ERP."

"You must pass one exam ($500) for your desired track/product. Options include: Business Intelligence with SAP NetWeaver, and Financial Accounting with SAP ERP (2 options) among others."

Sorry, Can't help more.

As NitWitNick said, " Certifications are good if you have the experience to back them up. ". So, it is essential that you get experience of working on ERP and CRM systems as a BA. Most roles for a BA with such experience will prefer you to have experience in a specific ERP or CRM system, so try to work on one that is in demand. I know this is easier said than done, as you can only work on the projects and systems that are available to you, but if there is such a project or system where you work now, try to get on it.