Lord Perversor wrote:any of the new starter boxes may come handy.
Either the start collecting 3x windriders 1x farseer 1x Grav tank
or the armored one 5x Dire avengers 1x wave serpent , also both boxes combined should be around your price range.
Solid advice. I'd also recommend seeing what appeals to him about the elda. Are there certain units he likes the look or idea of? Is there a specific craftworld that he's drawn to? Eldar are very diverse, and you can potentially ignore big chunks of the model line if you're drawn to certain themes.
If he wants to be highly mobile or hard-hitting, or if he just likes the idea of "wild elves" on jetbikes, Saim-Hann might be a good direction to go. That's the red and black paint scheme you see on most jetbikes in pictures. The seer+jetbike+grav tank start kit is great for this craftworld. The avengers+serpent option isn't bad, but you might want to consider simply buying more jetbikes or even a vyper (forthe jetbike core formation in the warhost).
If he likes the elegant, alien curves of the wraith units, likes the idea of an army of space elves that don't crumple under return fire, or if he likes the idea of a craftworld that epitomizes the "once-great empire backed into a desperate position" thing that the eldar do so well, Iyanden might be on your radar. Unfortunately, all-wraith armies aren't really an option any longer, but you can get a kill team or combat patrol up and running pretty easily. Consider investing in one or two units of wraithguard and maybe the avengers+serpent box. That doesn't really give you an
hq though...
If he really likes the aspect warriors, consider getting the avengers+serpent box and then mixing in aspects to taste. Banshees and spears are more difficult to make work, but all the other aspects are pretty potent right now. If he really likes a single aspect but isn't wild about others, you might even consider starting up a pale court detachment consisting of 3 squads of a given aspect and a farseer to join them. That should be right around $150.
Eldar can be built a lot of different ways. It really just depends on what he's looking for.