dead bulbs

We have four mesh light sets that I drape over the shrubs (for Christmas decoration). I put them on the shrubs on this past Saturday and last night when I turned them on, they were pitiful; some were on some were off in alternating sections. Today I stole good bulbs from one set and restored the other three. I have at least 15 dead bulbs. I'm sure I haven't found them all since the one sacrificial set is too stripped at this point for me to see what's working and what's not. They need to be 2.5V super bright green lights. I haven't found the right ones, but I've seen replacement bulbs priced at a pack of 3 for $1.39 or $1.99.  If I need to replace at least 20 bulbs, looks like I should expect to pay approximately $1 per bulb. So I suppose the best bet is to just buy a new set ... if they can be found.