Anacs

ANACS is one of the three leading coin grading services, the other two being PCGS and NGC. ANACS initials stand for «American Numismatic Association Certification Service» and as the name implies ANACS is associated with the ANA which is perhaps the USA’s oldest non-​profit coin collecting society.
All of the major grading companies, including ANACS, will authenticate, grade and then «slab» or encapsulate the coins in an air-​tight plastic holder to help preserve the coin. Grading and slabbing will in general enhance the value of your coin. The only exception to this is if the grading company mis-​grades your coin lower than what it should be — this will lower its value! There is an element of risk here, i.e. grading errors, but if you feel your coin was rated too low you can always crack it out of the slab!
The positives of using ANACS are:
1) They do not require a membership fee before you can submit coins for grading, NGC and PCGS do
2) Their grading fees are lower than PCGS or NGC. Right now ANACS is running a special where you can submit 10 coins to them for $ 119 which includes free return shipping. ANACS also has special rates for bulk submissions.
The main negative of ANACS is that coin collectors do not seem willing to pay much of a premium for ANACS graded coins. Collectors seem to pay the highest premiums for PCGS graded coins. Based on my experience I believe ANACS grades their coins quite accurately, at least as accurately as PCGS and NGC, and so I do not understand why there is a premium gap.
It is important to note that ebay does recognize ANACS (along with PCGS, NGC, and ICG) as being reputable services and these are the only grading services which can be cited in you listings (if you have a coin graded by any service besides these four you cannot advertise the grading of the coin.)
I like ANACS service but have been disappointed by the lack of market recognition of the value of ANACS graded coins. It is for this reason that I rate the service as a 4 instead of a 5.
PCGS = Professional Coin Grading Service
NCG = Numismatic Guaranty Corp
ICG = Independent Coin Grading Company