Those are some EXCELLENT points Trish! I think that remembering we are called to be cheerful givers is very important.
Really, from what I have learned in studying the Word, the reason for tithing the first tenth of what you receive is to protect against attacks. So financial blessing doesn't occur until we are sowing seed beyond that initial tithe. Personally my goal is to someday be at the point where I can give 90% and live off the 10%! I believe my God is a God of blessing and has prepared for me things greater than I can possibly imagine and dream for myself, so I am pretty excited.
However, as a successful businessman already, I can say that things were much harder and there is a definite uphill battle to increase my income before I began tithing. In fact, I was forced to begin erroding my moral stands to do it! It was only after I began tithing that doors started opening and my household became peaceful to the point where I was being blessed without having to live outside God's Word to do it. This is just my personal experience.
However, I want to bring to the Light another piece of Scripture that hasn't been talked about yet. Luke 16:9-13
9***And I say unto you, Make to yourselves friends of the mammon of unrighteousness; that, when ye fail, they may receive you into everlasting habitations.
10***He that is faithful in that which is least is faithful also in much: and he that is unjust in the least is unjust also in much.
11***If therefore ye have not been faithful in the unrighteous mammon, who will commit to your trust the true riches?
12***And if ye have not been faithful in that which is another man's, who shall give you that which is your own?
13***No servant can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.
For me, this was VERY clear, I think it is rather obvious that everything I have is NOT mine at all really but God's. I am very grateful and thankful for everything he gives me (this is one of the reasons we say 'grace' before eating meals btw, which again is not something specifically commanded by Jesus). You see, Jesus did not cover every single letter of law (like how much to give to the Church for spreading the Word) because he was trying to get across the ATTITUDE that we need to have. He came fulfilling the Law which was NOT abolished. Rather, he expanded upon what we knew of it previously (the whole concept of adultery and the such being committed in the heart as well is in reality etc.).
So lets look at this section real quick shall we? It follows the parable of the unjust steward. The key verse for me is verse 10. Here God says that if we are faitful in how we deal with unrighteous mammon (mammon may be read money btw) THEN we will surely be faithful in things that are important indeed! You see, the dealings with money aren't really important to God because do NOT worry God has plenty of money

However, it is rather just the SMALLEST way you can show your Faith. By being willing to give cheerfully 10% or more of your income you are showing Faith that God is your source and that no earthly matter supplies you with the things you need. Acting in Faith is always good because first off you will be blessed with more Faith by the Grace of God for doing so that you may do greater things in Faith.
Finally, sitting around worrying about paying your bills (and saying things like 'I can't afford such and such') is not how we are called to believe God takes care of us. Check out Phillipians 4 for more information on how we are to "be careful for nothing"
What better way to spend your money (granted by God) than to spread his Word so others might be as blessed as you? Seriously. If you KNEW God was going to pay your bills next month what would you do on Sunday when the collection bucket came around? Believe, expect and walk in Faith brothers and sisters. God bless you all.