I'm going to steel my post from another board to get some price overview:

LUX H8 V4 $225 LUX H8 V4 - Color Adjustable Angel Eyes | Lux Angel Eyes
dtec v7 $179.99 BMW Led Cree Hid Halo LED Angel Eyes E92 E93 E90 E91 M3 LCI Lighting Beru TPMS RDE008 RDE012 Dtec Mtec V3 V4 V8 H8 H11 Gp Thunder D1S
WeissLicht $149 WeissLicht LED Halo Upgrade Kit For E70 - BMW X5 and X5M SAV - 2007-2013 From bimmian.com
EAS - H8 High Intensity $149 EAS - H8 High Intensity LED Angel Eye Upgrade -- EAS014
Burger tuning H8 4 LED $129 BMW LED Angel Eyes - E90 E92 E82 E60 M3 1M X6 X5 Z4 - BurgerTuning.com
Hellst XRT V2 H8 $155 Order Hellst XRT V2
MTEC H8 V3 $230 Mtec H8 V3 CREE LED Angel Eye Halo Ring Bulbs BMW E92 E93 328i 335i 2007 2011 | eBay
eBay 20W H8 LED $45.99 20W H8 LED Angel Eye Halo Light No Error BMW 1 3 5 Series Z4 x5 x6 E90 E92 E93 | eBay
full LED headlights $6,500
retrofit OE 2011.5 headlights $2,000

Besides the full LED and the 2011.5 headlights, (as long as you go with LED bulbs and not normal bulbs) they are ALL pretty much the same.