We did everything (ceremony then reception) at the same venue, which was a big savings. We had ours at the Zoo in the botanical gardens. I didn't spend a penny on decorations as the site was one big spectacular garden! We had a small break between ceremony and reception for pictures (about 30-45 mins as the rest we did ahead of time), so none of our guests had to leave the site and figure out what to do with themselves and we had no transportation costs.
We chose a buffet, as it was not only cheaper, but I liked the idea that there would be less waste. People only took what they wanted to eat.
We made a donation to the Zoo in lieu of favours. I find favours are one of those really pointless traditions. Very few people keep them and I just hate creating more clutter and junk if I can avoid it.
I just asked each of my bridesmaids to wear a little black dress, rather than try to make everything match exactly. That worked really well. Noone had to spend cash on something that would never be worn again.
That's all I can think of at the moment.
Oh, one thing that I think is important is to question all the dozens of traditions and see if they are relevant to you and your OH or not. It's not just about saving cash - it's also about creating a meaningful ceremony for yourselves. It feels much better to choose the things that matter to you and leave out whatever feels like an empty ritual. Who cares what any of your guests think if you don't have favours or you want a backyard BBQ as your reception? If it feels right for who you are as a couple, it will be a genuinely lovely event for everyone. The wedding industry puts some powerful pressure on brides, in particular - be strong and don't be afraid to say no thank you!