Unpopular opinion: many aurei are overrated. Gold survives more easily than copper/silver so it's expected that they'll still exist. They're expensive just because they're gold but that doesn't make them superior. I'd rather have an exceptional denarius over an aureus any day of the week. That said, truly exceptional coins are worth the premium, provided they have superb style, pedigree, and other factors.
Ptolemaic tetradrachms can be very attractive, but are kind of boring because they all look pretty much alike, especially in using Ptolemy I's portrait over and over in later reigns. You might as well be collecting date sets of George Washington quarters. Roman Alexandrian tetradrachms are much more interesting and charming and fun to collect, and the portraits aren't nearly as ugly as a lot of people seem to think.
Unpopular opinion: You shouldn't quote reference numbers unless you understand how to use that reference and have verified the number. Likewise, it's not really worth trying to find reference numbers for references you don't own and can't verify anyways.
Chances are many of the coins in my collection come from 'unofficially' dug-up hoards, but I like them anyway.
I always check the ones I own or can find online (as by checking RIC numbers on OCRE or relying on authoritative secondary sources), but write down other major references as well in case I ever do get access to them.
The premium for provenance is an offering to gods that the coin was not wire-brushed, oiled/greased, thrown in vinegar/lie/other chemical or otherwise abused in the period the coin's existence is documented.
eBay is one of the best places to buy coins on a budget. There are still plenty of rarities to catch, and so long as you are careful with what you buy and who you buy from, you should be fine.
My unpopular opinion is that getting a coin in not exactly pristine condition, when the price is very low, is absolutely OK. Just 2 random recent acquisitions - these would be still affordable in nicer grades but I have no regrets - for me, a heavy wear, but still allowing attribution without doubts, adds to the coin's history
Amen! I was going to type something very similar! Every reference number I cite is from a catalogue at hand.
I wish I had said that! To me, catalog numbers are ways of finding the listing in the catalog so you can learn something about that coin rather than being the reason for being in themselves. I can gain something from data, for example, that a certain mint used 'IMP C' while another used 'IMP CAE' but my understanding is not improved knowing that a certain item is RIC 1234. Also there is the problem of catalog numbers incorrectly generated from concordance listings by people who ignore the fact that different catalogs based listings in different ways so not all coins with the same Cohen or Sear number will have the same RIC or BMCRE number. Christians on this list may see the similarity here of the situation that came with the original edition of "The Message" Bible translation. It included the full text in English translation but did not include verse numbers. Those who like to quote out of context were unhappy with losing easy access to favorite passages and the editors soon released a Message with those numbers (noting that the original texts did not have those numbers either but they were added later for easier 'study'). To me, coin books that add no information other than a number are not worth quoting. Quoting an incorrect number is much worse than omitting it altogether.
Philip I "The Arab" coins have the best style to cost ratio. Roman Imperial coinage is significantly more boring after 363. Auctions haven't been significantly more affordable than retail in the last year. 12 Caesars is a bizarre set for beginners because you pay through the the roof for 3 poor condition coins of insignificant emperors with boring reverses. The coolest coin in existence is the Tetrarchic Argentus with the four emperors sacrificing in front of the camp gate.
Purging my collection of most of my Greco-Romano ancients was a good choice I only miss one of them, fortunately.
You don't say? Galerius as Caesar, AD 293-305 AR Argenteus, 21mm, 2.7g, 12h; Rome, c. 294. Obv.: MAXIMIANVS CAES; Laureate head right. Rev.: VIRTVS MILITVM; The tetrarches sacrificing over tripod before city enclosure with six turrets. Reference: RIC 29b. From the Sallent Collection, ex-JAZ Numismatics.
Well, Roman provincials can be had for excellent prices sometimes. It seems like Roman collectors want official central government issues, whereas the provincial reverses can be very cool, with reverses reflecting mythology more often then the coins struck in Rome.
I think that given how common they are, the vast majority of the Tetricus I/II with Pax/Salus/Fides etc reverse types are about properly valued at $1-10 each depending on condition and style. Those with original reverses IMO should be valued much more. People also don't tend to appreciate how scarce types beyond Victorinus, Tetricus I/II, and Divus Claudius are.