Wort chilling

I was thinking without a wort chiller ways to cool my wort. One idea was: rather than boiling five gallons I would boil 2.5 gallons all with the same schedules and ingredients as if I was boiling 5 gallons and in the end just add the 2.5 gallon boil to a cool 2.5 gallons of water in my fermentor...would that be the same as doing a full boil?

I'm new to brewing, but when I made my first batch I just took my pot off the stove and set it in my sink and surrounded it with ice water. I did a 2.5 gallon boil.

Not the same as a full boil but it'll work. When I used to do partial boils I froze plastic gallon containers of spring water. Then when it was time to chill I sanitized the entire container and cut the plastic off with a sanitized razor blade. Chilled the wort in no time. Especially for hop utilization, it's best to do as close to a full boil as you can.

I do similar to jonk. I start my boil with about 4.5 gallons and by time I finish I have about 3.5-3.75gal of wort. I then add ice that I made the day before (after boiling water and sanitizing the pitchers) to get up to 5 gallons. Takes about 10-15min to cool the wort and it's free. I might get a wort chiller some day...but this works well for now.

2.5 gallons of over 200 degree wort + 2.5 gallons of cold water = hot wort in my opinion.

You will still have to do a small ice bath.

Now that I'm on my 7th batch of beer in the future, a wort chiller is on my list BIG TIME. Back when I started with Mr Beer, it wasn't that important, because you boil the water, turn off the heat, and then add your ingredients which drop the temp, then mix that with cold water. Doing all grain and partial all grain, you are boiling a ton more water, which takes a LONG time in a ice bath, and a wort chiller is well worth it. You would probably even do a cheaper wort chiller and still put it in a small ice batch in the sink.

I made my own wort chiller for $50 or so, counting tools needed (tube bender set). I had an old flaring tool so flared the ends slightly, and just stuck the tube on and used double clamps. Worked great. I do 2.5 to 3 gal boils. I also put it in an ice bath. The copper is the most expensive part, it was $35 for 20 feet at my local home improvement store.