Need some battery advice

[Silver Surfer]

Folks,

Old dad inherited his daughter's 390E upon her graduation from college.

The original battery went kaput. Would like to procure a replacement. My research on the Web shows a dizzying number of suppliers and a wide range of prices.

Would someone with experience in these matters direct me to a seller who deals in dependable products at a fair price.

I also assume that a lithium ion battery would be preferable to the NiMH type? Any battery brands to avoid?