mercenary shopping.

[PseRamesses]

My fav combo of mercs is 8-12 hoplites, 4-6 cretan archers, 2-4 bastarne and 2 sarmatian cavs. Easy obtainable from the start and frequently re-emerging, highly versatile and defensible impregnable. Playing mostly in or around the eastern Med I do always tend to get Cretan archers, Sarmatian/ Scythian horse archers and Bedouin camel archers for armies in thoose regions.
It´s a pity though that the merc pool in RTW is so small, compared with MTW, and europe only have 2 mercs - barb.inf. and barb.cav. Africa has only 2 also so there´s not much to shop around for is there? Try out RTR 6.0 it has alot of diff units and mercs - most enjoyable and best on the market, so far.

[RTW King]

If you want a mod to help with your merc army, my V2 Realism mod in my sig makes mercenaries appear significantly more often and creates more at start.

[pezhetairoi]

You can also edit the descr_mercenaries text file to raise chances, starting numbers, merc max numbers, and speed of regeneration.

For the best recruitment grounds, Asia Minor in general is best, with an extension into the north to get Scythian mercenaries. You get hoplites and thracians and bastarnae (the balanced army the Greeks never had and the Thracians seem incapable of creating) as well as more-than-sufficient firepower support from Rhodians, Cretans and HA. Heavy cavalry will be provided in the form of Sarmatians, Bedouins and Arabs if you so choose to extend your recruitment run into Dacia or Syria. The optimum would be barb cav, but that's as good as saying run through the entire known world which defeats the purpose of localised recruitment.