Wealthy with what you have
Seneca knew wealth. He was both popular and prosperous, allowing him to mingle freely with the aristocracy of Rome. With his exposure to the rich and powerful, he was quick to realize that wealth alone did not equate with happiness. Wealth was OK if you came about it honourably. So, nice if you can get it. Nothing to be ashamed of. But Seneca (in On a Happy Life) would caution us: we should own wealth, not be owned by wealth.
Wealth was not seen as "problematic" to the Stoics: it was a "preferred indifferent".
Indifferent because wealth - by itself - is neither good nor bad.
Preferred because it was handy to have, and it could be used for good.
In his 2nd letter to Lucillus (Letters to a Stoic), Seneca questions how one measures wealth and postulates that a wealthy person is actually poor if he is never satisfied with what he has - if he constantly thirsts for more.
Psychologists today apply the term "hedonic adaption" to this same process - growing tired of the things we have recently acquired, then wanting something new to fulfil our desire. Happiness is hard to hold onto, when you grow tired of what you have. So - for the Stoics - it was important to learn to love the things, you already have.
Seneca goes on to suggest (in letter II), that you have enough "wealth" when you have the things you need, and you have just enough of those things. In a similar vein of thought, Marcus Aurelius encouraged us to be satisfied with what we have, instead of worrying about what we don't have. You can appreciate what you have more, by imagining what it would be like to be without them. Meditations 7:27
Marcus also warns us not to become too attached to the possessions we have: we should not become distraught if we lose them. By seriously contemplating what it would be like to lose the things you have right now, your appreciation for them increases. See more on this in Stoic Exercises / Good Negativity.
Epictetus (in Fragments) tells us that to be dissatisfied with what you have, is to be unschooled in the "art of living". Whereas, to make reasoned use (best use) of what you have - what you are given by fate - is an admirable quality.
Rather than relentlessly pursue material things, the focus should be on enriching the body, mind, spirit and community. A much better use for wealth.
Today we see many people living or aspiring to "minimalist" lifestyles, wherein a constant craving for more is shunned.
Less can be more!