Around 900,000 tickets for the London Olympics have gone on sale with priority given to unsuccessful bidders from the previous two rounds.
Those eligible for the sales which include tickets for the men's 100m final were contacted directly by the company Locog via email. Any tickets unsold during this period will go back on general sale from 23 May at 11:00 BST.
BBC News website readers have shared their stories of trying to secure tickets to London 2012.
Richard Grose, London
It's a dream come true - for once it paid to be one of the 20,000 unluckiest people in the country!
I've just got four tickets for the Men's 200m final.
The tickets will cost me £600 plus postage and I plan to take my dad and two brothers.
The system worked perfectly this time round - just hope I don't get another email telling me it's another mistake.
Andy Cole, Ampthill, Bedfordshire
I am one of the one million who are eligible for this week's sales.
So far I have spent about six hours repeatedly trying different events, ticket values and quantity combinations with no success.
I did note with interest that there are still multiple tickets available for the best events if you have deep pockets.
As of Sunday night, you could still buy four tickets for athletics if you had £2900 this is the same for the closing ceremony at over £600 a ticket.
All the sessions disappeared in ascending order of ticket value, so it would appear the most important thing to buyers is price, not event.
What is most annoying is that the listings did not update in real time. They show certain ticket prices but you have to request them and then wait, only to be told they are not available.
I guess that after the first five minute wait, everything else was gone.
Wayne Davis, Tewkesbury
At first it didn't want to work.
I kept inputting the session code and it kept telling me to add to my shopping basket (which I was doing). After five minutes of frustration it seems to have worked, we seem to have swimming final tickets please let this be for real!
So excited! I've been following the Olympics daily since before the government announced they would support it. I can't believe it!
I had been sitting patiently, but nervously, at my computer hoping that the system worked this time but it's wasn't being updated manually and I was worried.
I didn't know what I would have done if I hadn't got tickets but fortunately I don't have to worry now.
Wendy Chappell, in St Neots
I tried again today for tickets.
I applied for the lowest priced tickets £50 for all the swimming and cycling events that were available.
Even though £50 availability came up in the price box, all my requests were refused.
We went to the test event on Saturday 5 May, so we have seen the Olympic Park, which was what we wanted to do.
We had no problem getting tickets for that at all.
The rest we'll watch on TV because I'm not trying again.
It has to be the most convoluted, illogical and unfair way of selling event tickets that I've ever come across.
We tried for athletics, canoeing and anything really, including events outside of London as my husband likes water sports but we can't get that.
It is such a stupid system.
Why doesn't the website tell you the tickets that are available as opposed to it showing you everything so you click on it to find out down the line that tickets for that event have already been taken?
I love the way they say tickets for the 100m men's final are available.
Yes they are but for £750 a time - for that sort of money I'd want to be on the track standing behind Usain Bolt carrying his basket.
Suzanne Salmon, Bexhill on Sea
Third time lucky! I was quite disgruntled previously at the way the tickets were sold.
I didn't like the fact that all the tickets were on show even if they weren't available.
I had resigned myself to not getting any tickets until the arrival of an email saying that I had another opportunity to apply for tickets.
I logged on, clicked on opening ceremony tickets and was able to purchase four straight away. Fantastic!
I am one of the lucky ones who got tickets in the second round of balloting but how on earth have they managed to release an extra 5,000 tickets for the men's 100m final? Surely they should have been priority in the first and second rounds when people were trying ridiculously hard to get those standard of tickets? Locog again have questions to answer about the ticketing process. Jack, Middlesbrough
Applied for two Men's 100m tickets, got them! Amazing! Emotional at the thought of being there! Jon Platts, Mountsorrel, Leicestershire
After nearly one hour of trying, we got two £300 tickets for the men's 200m final. Very very stressful but absolutely ecstatic! Makes up for getting nothing before! Michael Sewell, Radlett
I applied for tickets for the men's 100m final night (even though these weren't listed) and was successful in getting three tickets for £295 each. I am planning to take my wife and six-year-old daughter. It will be a fantastic experience for all of us and hopefully we will see history in the making! David Beyer, Melton Mowbray
Missed out first round, am in this 'exclusive' pre sale but cannot buy any tickets! The search filter is meant to include/exclude availability of tickets though when you try and reserve tickets the system states that there are no tickets available! It is a dreadful system, whoever signed it off should be fired. Sam Johnson, London