No, it currently has to be money or goods (donations in kind). Which makes sense. After all, how do you financially quantify volunteer time for a church?

No. Good intent as a volunteer isn't acceptable. Cash/hard goods.... is the name of the game. Any measure of gain, even the smallest measure without tithing deems you unworthy. It's all God's money anyway but LDS focuses on 10%. Jesus would accept your volunteer services but LDS is not and never has been about Jesus.

Read what Jesus said about the little old widow that gave her last cent. It is not the amount , you have to give what you got with the right "frame of mind" or "heart".

A "tithe" is 10% of your INCREASE. You do not INCREASE your time. There is no "time bank" or "time stable" or anything of that sort. You cannot donate intangible assets as a gift from your "increase."

Whether or not you are a full tithe payer is, to a certain extent, open to your own interpretation. Nobody goes through your bank statements to audit your tithing contributions. The Bishop simply asks if you are a full tithe payer. However, if you obviously have had income and have paid nothing, I'm not sure what the Bishop would do with your temple recommend. To that extent, what constitutes a tithing contribution is also a matter up to the interpretation of the Bishop. Bottom line. If you're having trouble paying your tithing, go speak to your Bishop. This would be an indication that you're in serious financial difficulty. The church counsels members in such difficulty, and can sometimes provide some assistance. In the past, there have been occasions when individuals have rendered special service to help fulfill their tithing obligation. I know of no modern examples, but the idea of rendering service in order to fulfill the Lord's commandment to pay tithing is by no means antithetical to the principle of tithing. However, regular church service certainly doesn't count, and so paying tithing through some service rendered presents something of a dilemma in being difficult to quantify separate from your other obligations as a member. Fortunately, the Lord's not particularly interested in the numbers so much as our obedience to a principle and he knows what he will accept from you. The only person who can give you a definitive answer to this question for any individual's specific circumstances is the individual's Bishop and if this issue ever becomes important (after assistance from family has proved insufficient) one should certainly speak to one's Bishop. It is not a virtue for a man to hide his need from his friends and his leaders, but rather the greater virtue is in being honest and forthright, eschewing pride, that the ward may be enabled to fulfill the Lord's call for us to share one another's burdens. How can anyone share your burden if you will not let them? Optimally, your Bishop will not be the first person to have heard about your potential difficulty before the time comes for you to speak with him. The very first people you should make aware of your troubles, or potential troubles, are your home and/or visiting teachers, who should report to their president (EQ or RS). Depending on the need it may then be referred to the Bishop.