spells that are actual problems-
Summon Monster VII+, used to summon a djinni. the summoned creature has major creation 1/day with vegetable matter summoned being permanent. CL is 20, resulting in 20 cubic feet of the vegetable matter created. on the commodities list in the PHB, Saffron (flower pollen) or cloves (flower bugs) are listed at 15gp/pound. a cubic foot of ground cloves is 27.44 pounds, or saffron at 8.97 pounds/cubic foot. so, the Djinni can create 548.8 pounds of ground cloves, a commodity values at 8,232 gp, per djinni summoned. furthermore, the djinni can also create 40 gallons of wine(1 large barrel full, worth 10gp 6sp+), and food and water to feed 60 humans for a day. so any wizard of level 13+ should be able to destroy the price of spices and wine fairly quickly, as long as he can cast conjuration spells. its also a good source of darkwood (which we do not have a known density for).
wall of iron (caster level 11+) costs 50gp of gold dust(1 pound), and creates a minimum of 2.75" thick, and 11 5' squares in size. that is 108,900 cubic inches of iron, or 30,960.27 pounds at 1sp/lb, valued at 3,096 gp 2cp per casting. a conjuration specialist would be able to cast this twice a day, for a profit of 6092 gold per day at level 11. even if we nit-pick the thickness to 2", its still a ridiculous profit despite being a difficult shape to deal with. one mid-level conjurer could quickly flood the market with iron.
the problem originates with a spell being able to easily make profit appear from nowhere. easy to fix, simply by making a few edits to how the world interacts with magically summoned materials in the medium to long term. the short term in this case is one adventure, lets say a month. if the trade goods evaporate or degrade in a couple of months, then they wont be worth much. the spell effects are balanced, on their own in their original intent for use in tactical combat. its only when they hit the new rules in 3e for commodity value that they break the economy.
there are probably a few others that i haven't noticed yet, but those are the big two. i once ran a game where a subplot was the royal wizard abusing these two spells.