Budget is never, ever, ever a reason to breach etiquette.
Rant: I have gone to several weddings lately for couples with limited budgets. I understand having a budget, really, I do. It's never a reason to treat your guests poorly. I know that some people think that the wedding is about the bride and groom, but really, if you care enough about people to want them there, you should care enough about them to treat them well. I think the ceremony is pretty much about the bride and groom (who care if they don't like your vows?) but the reception is really hosting an event for the guests.
1. If you want to have a cake/punch reception, don't JUST have cake/punch. Have cake, apps, and a variety of snacks. Your wedding should be between 2-5, or after 8.
2. If you want to make food yourself, don't do it if you have more than 50-60 people coming. It's reasonable to cook for that many people. Don't serve your guests cold or measly food because you wanted to make it yourself.
3. Don't invite people to only part of the wedding. If they are invited to the ceremony, invite them to the whole reception, and don't invite people after dinner.
4. It's better to cut your guest list and do it right than to have a large guest list and treat everyone poorly.
5. Absolutely do not use bridal party and family as servants. Yes, it's okay for them to do small helpful tasks if they offer. I went to a wedding where the groom's mother spent the whole time refilling food and drinks on the buffet table. I felt so sorry for her not getting to enjoy her child's wedding. Yes, people are willing to do stuff like that sometimes, but treat people better than making them unpaid servers.
6. I don't mind an outdoor, super casual, BBQ type reception. I still hate having to wait an hour for food, I still don't like flies getting on my food, and I still need somewhere to sit. One grill or one buffet table is not enough for 200 guests. 100 chairs is not enough chairs for 200 guests.
If you need to cut your budget, don't do it at the expense of your guests. It's okay to just invite 20 people to your wedding. It's okay to not give +1 to truly single guests. It's okay to serve hamburgers and potato salad. It's okay to not have chair covers or uplighting. It's okay to have your wedding in a church gym or rec center.
I THOUGHT these were basic, common sense type of things, but after all the weddings I've gone to like this, I needed to say something.