$1, eBay seller nile-ancient-coins, February 2015. A buddy of mine sells coins at shows and on eBay occasionally. This interesting type struck under a Roman quaestor in Macedon after the Third Macedonian War had apparently been in his trays for a bit and was time to go. I thought it was a crime that it had no bids so I placed the opening bid on it and won it at that price. He still says it's the best deal he's ever given anyone. Macedon, Roman Rule, Æ22(10.65g). Gaius Publilius, Quaestor, 168-167 BC. Head of Roma right, wearing winged helmet terminating at the top in the head of a griffin. Border of dots / ΓΑΙΟΥ ΤΑΜΙΟΥ ΠΟΠΛΙΛΙΟΥ in two lines within a wreath of oak-leaves. Above, monogram. Line border. MacKay, "Bronze Coinage In Macedonia, 168-166 BC," ANSMN 14 (1968), pp. 5, pl.III, 2; SNG Copenhagen 1320. $20, Aegean Numismatics, Vcoins, June 2016. This isn't a great coin but it was a nice introduction to an interesting facet of Republican numismatics that I was very interested in but didn't know enough about to feel confident spending big bucks on. I was already paying shipping for another much nicer(and more expensive) RR bronze so I tacked this guy onto the order. Sicily, uncertain Roman mint, Æ as(21mm, 5.37g). Anonymous("AV" or "AN" monogram), circa 200-190 B.C. Laureate head of bearded Janus; I (Mark of value) above / AV or AN monogram within wreath. Hoover HGC 2, 1690; CNS I 77; BAR issue 37
In my experience, the best bargains today with the wide availability of internet use by even the most ignorant sellers, tend to be overlooked LRB rarities. Both coins below are rather rare variants of otherwise extremely common phoenix on pyre Fel Temp variety. What makes them rare are large symbols in the right field. They were either simply ignored as in the first example, or under-appreciated as in second. So I got the first one for around 5 dollars, and the second for around 20 dollars - both purchases in late 2016.
Here's a sestertius collection I found on eBay this year. They were in separate auctions - I am using the seller's photos here (better than mine except for the fingers), but the description was vague. Prices paid: Gordian III - $15.16; Maximinius Thrax - $18.17; Philip the Arab - $13.27.
Like TIF, my best deals in this range have come in group lots. (Either that or they betray my age.) But I thought I'd add that nice Islamic coins can be obtained very inexpensively, e.g. the following dirham of al-Ma'mun (810-833), Baghdad mint, AH 198, for $20 all-in:
How about a few more as we wind down this thread?... Bargain Bin is the perfect category for when something outside of your regular collecting interest catches your fancy. This Byzantine Leo V AE was $7. BYZANTINE EMPIRE. Leo V AE18. 2.09g, 18.1mm. Syracuse mint, AD 813-820. Sear 1638. O: Frontal bust of Leo V with cross crown and Loros, holding cross in his right hand. R: Frontal bust of Constantine with cross crown and chlamys, holding cross in his right hand. A couple of years ago, a few members here on CT started a Gallienus Panther Club (sounded less silly back then ). This $6 entry was the price of my admission. GALLIENUS AE Antoninianus. 3.82g, 21.3mm. Rome mint, AD 261-268 AD. RIC 230; Sear 10281. O: GALLIENVS AVG, radiate bust right. R: LIBERO P CONS AVG, panther walking left; B in exergue.
Under $20... Great thread @zumbly ! $10USD Valens, AD 364-378 AE Reduced Follis, 17mm, 2.3g, 6h; Aquileia mint, AD 364-378. Obv.: DN VALEN-S PF AVG, pearl diademed, draped, cuirassed bust right. Rev.: SECVRITAS-REIPVBLICAE, Victory walking left, holding wreath and palm branch. Wreath in left field // SMAQS Reference: RIC IX Aquileia 12b (p. 96), type xiv(b) (p. 92) $6USD RI Gallienus 253-268 CE Ant Abundantia $10USD RI Aurelian 270-275 CE AE Ant receiving Globe from Jupiter $17USD RI Constantius II 337-361 CE AE 2 Soldier spearing downed horseman $8USD RI Licinius I 308-324 CE AE3 Jupiter w Eagle