As far as I know, LifeExtension does most of their tests through LabCorp. Peak and I are working on putting together a list of online lab tests/providers which offer the best deals. There is no single online site that offers the best deals. Each site has it's bargains and it's ripoffs unfortunately. I have done too much research into this because I have a sort of OCD for value.
Here is a quick list that I made of common test panels... if anyone has found better deals please chime in.
LEF (membership req'd $5 per month)
$137 Amino Acid Panel (great deal as it is $600+ through your doctor without health insurance)
$75 Male Basic Hormone (T+free, E2, PSA, DHEA-S)
$28 Zinc, serum
$47 Copper, serum
$59 Thyroid Profile Plus (TSH, FTI, T3 uptake, T3, T4, free T3, free T4)
$69 Anemia Profile (Iron serum, TIBC, ferritin, B12, folate, CBC, reticulocyte count)
$84 Wellness Profile #3 (only during December when 50% off, contains all basic tests plus HbA1c, vit D, CRP)
$57 Dihydrotestosterone (only March when 20% off all tests)
$37 Prolactin (only March when 20% off all tests)
$135 Hormone #1 Women, contains E2, Pg, T + free, Cortisol, FSH, LH, DHEAS (only order in March when 20% off, men can order this too)
$71 Vitamin A, E, Beta-Carotene (only order in March when 20% off)
$79 VAP ($69 with a $10 off coupon on local lab site)