Baseline Reference Prices

Note: The above rates would be set by buying power. So as the currency gains in buying power, the hourly rate may decrease by a fraction of that.  However decreases should only reduce by a fraction of the increased buying power - so there is always /effective/ wage growth.  As more staff are paid in Marscoin it may also be necessary to correct the pay rate so outgoings do not exceed income.
Explanation:
This correction should not reduce buying power.  If 20 marscoin today can buy 10kg of platinum, then after a rate correction for example down to 10 marscoin a day, it should have enough buying power that 10 marscoin still buys 10kg.  (Or if we use the "Fraction rule" 10 marscoin can buy 10.5kg)

The optimistic ideal here is everyone earns equivalent pay scales based on experience or qualifications. This puts everyone on the same playing field.  Non specialists develop into specialists, and specialists can cross train into Diploma level.  In all levels equivalent incomes can be achieved depending on hours worked, overtime and risk.   Planetwide income equality.  This also assumes certain basic human rights with regard to life support being a unified system for everyone. This would eliminate the need for something like a universal basic income. Colonists should not need to pay for breathing and eating - so those not able to perform work would still be able to eat sleep and breath.

Although this does give a small possibility for a lower class system forming for those not actively performing work.   In this situation safeguards should be in place to make sure everyone has some sort of earning potential available to them outside of basic survival needs. Best case scenario - allow universal computer access for all, so they could engage in basic investment/commercial activities, worst case scenario have regular rotations of mining, exploration and extraction expeditions which willing participants can sign on for regardless of their skill level.  Some communal facilities such as machine/tool workshops, 3d printers, etc could be maintained so that otherwise idle colonists can create equipment or art which they can sell.        Ideally however the employment needs should scale proportionally with the growth of the colony so nobody finds themself idle.

Taxation:

AKA Funds pooled for use by the colonial leadership steering committee to develop the colony further. This could work simply as a product of automatic Marscoin network transaction or mining fees - Colonists have better things to do with their time than waste it filling out busy-work tax return forms for incompetant bureaucrats.

Levies and Duties could however be applied to imports or exports to self fund the logistics facilities involved but this would have to be strictly controlled to avoid abuse or pointless paperwork. Also freight charges could also be a typical factor for the transport companies. This would also allow those same busy-work incompetant bureaucrats on Earth to mutually benefit from interplanetary trade - by applying duty fees on materials sourced in space at the point of sale on Earth.  Let Earth worry about the paperwork, space pioneers just want to get paid at the end of the day. Let the people on Earth; benefitting from the work,  pay the Duty costs. Leave the pioneers out of it.

Resource Price rates:
Would depend on scarcity or glut of given resource extraction on Mars or on accessible asteroids, and its usefuleness to a Mars colony. Transportation, extraction times, and ore processing could also be a factor.   As such many prices may vary between raw ore per ton, and refined materials  per ton.  As local resources are exhausted this potentially may apply an upward pressure on prices, but this should be offset by the raw volume of material available. The universe is virtually infinite. It may cost more to dig out iron - but you are digging out so much more the volume keeps the price down regardless.

Limited usefulness Trade Commodities (eg Diamonds, Gemstones, Geological samples, Art, Artifacts etc)

Precious Metals (Gold/Silver/Platinum/Lithium)

Specialist Metals (Aluminum/titatium/uranium/tin/Magnesium etc)
Sundry Metals (Iron, Copper etc)
Sundry Resources (water/basalt/regolith/percolates etc which can be used in life support systems and construction)

Sundry Materials (Rare Earths, sorbent and MetalOx materials useful in CO2 scrubbing and other reactions)

Chemicals (Any chemicals, solvents, acids, oxiding agents etc)

Transportation costs:
These could easily settle into fixed rate based on easy to deal with factors like origin, destination, size, speed and quantity.  It is expected that eventually a standard rate would evolve naturally here.