Financial questions in UK Standard Visit Visa.

I live with my family so incur no living expenses and my mom pays my university. I make only around 100 GBP each month and only use it for my shopping and it is just a parttime evening job so no confirmation.

So you can use that 100GBP as your parents' money they give you for living.

1. Do you have another income or any savings? No?

1. Yes, from your parents 100GBP per month + 230GBP your mother pays. So you get 330GBP from parents. They will ask evidence of your mother's salary.

2. How much money are you planning to spend on your trip? I paid 745 GBP for the flights so should I put around this amount of money or estimate some other shopping and sightseeing stuff or put the 6500gbp as in the savings book my mom allows me to use?

2. Include flight, accommodation, pocket money, food money. The pocket money includes shopping, dinners and sightseeing stuff. That should be estimated by you. For example 15GBP per day - that is one museum or one outside launch plus 20-30GBP for food per day (even in case you will eat in his mother house). Sum 745GBP+number_of_days*(15GBP+25GBP) and it is fine.

3. What is the total amount of money you spend each month? The system does not let me put 0 here so should I roughly state the amount my mom spend on me and my university ~230 gbp/month?

3. That's right - food and other costs you have in usual life. Answer 230GBP. They want to know whether you are able to meet your cost based on income or not. As you do not have legal income they will see whether your boyfriend's mother is able to meet your living costs or not.

4. I put my boyfriends mom as the first sponsor but it asks how much money will they be paying towards your visit? How should I answer this question because I stay at her house and have meals with her so I can not estimate how much money that should be?

4. As I understood his mother will pay towards you, so you should answer equally to the point 2 but without flight in case, you will pay it by yourself. Answer is number_of_days*(15GBP+25GBP)

5. Will you be travelling in the UK with someone who is not your partner, spouse, or dependant? should I put my boyfriend name here - we wont leave Vietnam together but will fly back together

5. Definitely not. This point for those who will leave Vietnam with you.

6.Should I put anything in the Extra information section as it says: If you needed to add more information but were not able to, you can write it here?

6. Put that you are going to leave England or will return to Vietnam after the travelling in order to keep working/studying and so on.

Also, there are a question asking if I ever get refused for the visa - there is no stamp in my passport about the first refusal - should I be honest with this question?

Always be honest in your soul and with UK government :)