IMO, I think the best pearls for the buck are from www.pearlparadise.com
. I believe Mikimotos are just branded Hanadama akoya pearls (the highest grade of akoya pearls). You can get non-Mikimoto branded hanadamas through Pearl Paradise for a fraction of the cost, and they'll likely look just as good. You can get a set of 7-7.5mm Hanadama pearl studs for $230. Alternatively, you can get a set of 8-8.5mm "regular" akoya pearl studs for $185.
However, if you're on a budget, I'd highly recommend the "Freshadamas" that Pearl Paradise carries. These are fresh water pearls that closely resemble the luster of akoya/hanadama pearls. However, because they're fresh-water pearls as opposed to salt-water, they're 100% nacre (the calcium secreted by oysters that is basically the "pearl"). Salt-water pearls, on the other hand, are made up of a shell center and a thin coating of nacre (about .5mm for akoya pearls). Therefore, over time, the thin nacre coating on salt-water pearls can wear away, causing the pearl to lose some of its luster. This is not a concern with fresh water pearls. More importantly, these fresh water pearls are a fraction of the cost of their salt-water counterparts, and arguably, look just as good. I got my gf a pair of these for Valentines day, and she loves them. You can get a pair of 8-8.5mm Freshadama studs for $99, and a set of 9.5-10mm studs for $131. For the money, you'd be hard-pressed to find a better value.