Most carpetting plants will also need a nutritious substrate
Nothing NEEDS a nutritious substrate. Everything needs nutrients. Where they get the nutrients from is the question. Nutritious substrates are mainly a back up for if you forget to dose the water column. Many people grow all sorts in setups with plain pea gravel including HC, glosso etc.
Plus a nutritious substrate doesn't really fit into the 'budget' theme unless it is a compost type and then you will need to water change and will definately cycle at the beginning.
Photos as promised bit late because I had to get the kids from school then cook some Octopus for dinner, then couldn't get on the PC because the one upstairs is down until tomorrow and the wife was looking at silly priced fancy muslin squares and I daren't interupt her in case she buys them to pee me off. Just to introduce this little tank's story first:
Tank was bought 4 weeks ago at circa 10am. It was £15 and had a pink rim and bottom.
10-30am took top and bottom rim off and sprayed black. Put supplied pink and white gravel and crystal butterflies away in my 'for future scapes' box

11am put rim and bottom back on and put in bottom of emersed cupboard, noticed floor was 'bowed' so put a folded teat-towel under it to 'fill the voids a little.
11-10am put 1 full 2kg bag of new non pink and white gravel in the bottom.
11-15am Put 23 litres of fresh tap water in.
11-20am put some plants from my main tank (was in a holding state at the time)
11-25am Put filter in and plugged it in.
11-30am Started acclimitising shrimp.
1-30pm released the shrimp.
So this is 4 hours after I bought the tank (its actually today and 4 weeks on but looks pretty mcuh the same to me. lol.) No idea what media is in the filter. Didn't open it up, just put it straight in. Mainly wanting flow so doesn't bother me what gubbins is in the compartment at the bottom. Most likely sponge I should think. The light is 3 x 3W 5500K LEDs (underpowered so it is actually 7.35W (1.2WPG which in LED terms is super highlight equivalent to circa 4WPG IMO or 2x equivalent T5HO) that were over some emersed tubs that I moved out (mosses that went into the main tank.)
This is it's home in my emersed cupboard:
And I think these shrimp are alive 4 weeks later
Summary :
New tank
New gravel
Unmatured filter
Fresh Tap water
Good amount of plants
No water changes
No CO2
0.5ml NPK/0.2ml trace weekly
= No cycle, no new tank syndrome, no livestock deaths
NOTE= If I had chosen to put compost or a nutritious substrate underneath I would have done water changes at the start (or at least until I got lazy and couldn't be bothered to)
Like I said earlier. This isn't a show tank, no scaping. More a 'holding area for plants I'm not using just like the emersed tubs above it. It's also another space to breed shrimp
p.s. Tom Just in ase you're worried about stressed shrimp yours came out of the main tank. lol. There are only 30 or so in this tank at the moment until the population explodes
Andy